TY - CONF A1 - Szymoniak, Paulina A1 - Madkour, Sherif A1 - Schönhals, Andreas T1 - Dynamics of nanoscopically confined PVME in thin films of an asymmetric miscible PVME/PS blend N2 - In recent years, substantial efforts have been devoted to investigating nanoscopic confinement of polymers, and its effect on glassy dynamics. Broadband Dielectric Spectroscopy (BDS) was used to study the dynamics of ultra-thin films of PVME/PS 50/50 wt% blend, employing a novel nano-structured capacitor sample arrangement. The investigated system shows a complex dynamic behavior. First, an α-relaxation, related to a bulk-like layer was found. Second, an α’-relaxation was observed, characteristic for dynamically asymmetric blends, where the out of equilibrium dynamics is attributed to weakly-cooperative PVME segments relaxing within a frozen environment of PS segments. Third, for thinnest films, an Arrhenius-like process was dominant in the dielectric spectra, indicating localized fluctuations of the segments. Relaxation rates of this process resembled that of the degenerated α-relaxation of the adsorbed layer, found for pure PVME [1], thus it was assigned accordingly. For thinnest films, this process undergoes a further confinement, due to the topological constraints, introduced by PS. Such multiple confinement effect has not been reported for ultra-thin films of polymer blends, before this study [2]. [1] Madkour, S. et al. ACS Appl. Mater. Interfaces 2017, 9, 7535. [2] Madkour, S. et al. ACS Appl. Mater. Interfaces 2017, 9, 37289. T2 - 10th Conference on Broadband Dielectric Spectroscopy and its Applications CY - Brussels, Belgium DA - 26.08.2018 KW - Polymer blends KW - Thin polymer films KW - Dielectric spectroscopy KW - Specific heat spectroscopy PY - 2018 AN - OPUS4-45919 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina T1 - Rigid amorphous fraction (RAF) in epoxy/Boehmite and epoxy/LDH nanocomposites N2 - The interphase between the inorganic filler and the polymer matrix is considered as one of the most important characteristics of inorganic/polymer nanocomposites. The segmental dynamics of this interphase is expected to be altered as compared to the pure matrix, which might percolate into the entire system. For instance, it was found that a so-called Rigid Amorphous Phase (RAF) is formed by adsorption of segments onto the nanoparticles yielding to its immobilization. The RAF is available from the decrease of the specific heat capacity Δcp in the glass transition region of the nanocomposites. Here, precise Temperature Modulated DSC (TMDSC) was employed to study Δcp of epoxy/Boehmite nanocomposites with different nanofiller concentrations. Surprisingly, the investigated system showed an increase of Δcp with increasing filler concentration up to 10 wt%. This implies an increased fraction of mobile segments, and is in accordance with the found decreased value of the glass transition temperature Tg. Although for higher filler contents Tg further slightly decreases, Δcp decreases in contrary, indicating a formation of RAF. This behavior was discussed as a competition of mobilization effects, due to an incomplete crosslinking reaction, and the formation of RAF. T2 - 15thLähnwitzseminar on Calorimetry 2018 CY - Rostock, Germany DA - 04.06.2018 KW - Nanocomposites KW - Rigid amorphous fraction KW - TMDSC KW - Boehmite PY - 2018 AN - OPUS4-45148 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zorn, R. A1 - Szymoniak, Paulina A1 - Kolmangadi, Mohamed Aejaz A1 - Wolf, M. A1 - Alentiev, D. A1 - Bermeshev, M. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Low frequency vibrational density of state of highly permeable super glassy polynorbornenes – The Boson peak N2 - Inelastic incoherent neutron time-of flight scattering was employed to measure the low frequency density of states for a series of addition polynorbornenes with bulky side groups. The rigid main chain in combination with the bulky side groups give rise to a microporosity of these polymers in the solid state. The microporosity characterized by the BET surfaces area varies systematically in the considered series. Such materials have some possible application as active separation layer in gas separation membranes. All investigated materials show excess contributions to the Debye type density of states characteristic for glasses known as Boson peak. The maximum position of the Boson peak shifts to lower frequency values with increasing microporosity. Data for PIM-1 and Matrimid included for comparison are in good agreement to this dependency. This result supports the sound wave interpretation of the Boson peak. KW - Polynorbornes KW - Neutron Scattering PY - 2020 DO - https://doi.org/10.1039/d0cp03360j SN - 1463-9076 VL - 22 IS - 33 SP - 18381 EP - 18387 PB - Royal Chemical Society AN - OPUS4-51165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina T1 - Spatial Inhomogeneity, Interfaces and Complex Vitrification Behavior of Epoxy and Corresponding Nanocomposites by Broadband Dielectric Spectroscopy and Hyphenated Calorimetry N2 - Polymer nanocomposites (PNCs) with inorganic nanofillers dispersed in a polymer matrix have been widely studied from the 1990s, since the pioneering work by Toyota Central Research. The possibility of producing advanced tailor-made, light weight and low-cost materials, inspired academic and commercial research towards numerous potential applications, facilitating PNCs to become a billion-dollar global industry. The introduction of nanoparticles (NPs) to a polymer matrix is expected to result in improved properties. The outstanding performance of PNCs is determined not only by the characteristics of the used components but also by their phase morphology, including the dispersion of NPs and interfacial properties. Understanding of structure-property relationships is particularly important for polymer nanocomposites with high industrial significance, such as epoxy-based materials reinforced with inorganic nanofillers. These PNCs have been successfully adopted by the marine, automotive and aerospace industries, although they are still rarely studied on a fundamental level. Therefore, this thesis aims for a detailed understanding of the structure, molecular mobility and vitrification kinetics first, of two epoxy-based materials with different network structures and second, of the corresponding nanocomposites with different alumina-based nanofillers. The first system considered (EP/T-LDH) was based on bisphenol A diglycidyl ether (DGEBA) cured with diethylenetriamine (DETA) and taurine-modified layered double hydroxide (T-LDH) NPs. The taurine molecule bears additional functionalities that could enhance the interactions between the matrix and the nanofiller, improving the interphase formation. The seconds system (EP/BNP) was based on DGEBA and methyl tetrahydrophtalic acid anhydride (MTHPA) as a hardener, reinforced with boehmite nanoparticles (BNPs). The comparison of the two systems enables for a comparative study on the effect of different hardeners and the morphology and modification of the alumina-based nanofillers on the material behavior. The materials were investigated employing complementary techniques with different sensitivities and frequency windows. The following methodology was used: transmission electron microscopy (TEM), small – and wide – angle X-ray scattering (SAXS/WAXS), broadband dielectric spectroscopy (BDS), calorimetry in a form of conventional DSC and fast scanning calorimetry (FSC), as well as specific heat spectroscopy (SHS) in a form of temperature modulated DSC, temperature modulated FSC and static FSC by calculating the thermal relaxation rates from the cooperativity approach. The FSC method (based on adiabatic chip calorimetry to probe micrometer-sized samples) was successfully employed in this work, exploiting all its possibilities for the first time in literature for a PNC. Moreover, a systematic analysis technique was established to overcome the problem of vague glass transition regions observed for highly loaded PNCs in the heat flow and heat capacity curves. First, TEM, SAXS/WAXS and indirectly BDS and SHS were employed to obtain the information about the approximate morphology of the PNCs. It was found that epoxy-based materials exhibit a structural heterogeneity in a form of regions with different average crosslinking density. This was indicated by multiple-peak scattering pattern of the polymer matrix and two distinct α-processes (dynamic glass transition) related to the cooperative fluctuation of the epoxy network found by BDS and SHS. This was described for the first time for epoxy-based materials. The two α-relaxations were evidenced differently for the two systems, which is related to different network structures and dipole moments due to the employed hardeners. Nevertheless, structural heterogeneity is an intrinsic feature of these materials, independent of the type of hardener used for the network formation and nanofiller. In addition, matrix inhomogeneities were more pronounced with increasing nanoparticle content. Furthermore, a powerful new technique was applied for X-ray scattering data, using Monte Carlo fits, to describe the NPs dispersion throughout the whole sample volume (as opposed to the local investigations performed by most researches). Additional structural information of the two systems was extracted by BDS and SHS, such as qualitative and quantitative estimation of polymer segments physically adsorbed and/or chemically bonded onto the nanoparticles. Due to the immobilized character of this interphase with respect to the cooperative segmental motions, it is denoted as a rigid amorphous fraction (RAF). For instance, on the contrary to EP/BNP, for EP/T-LDH a dielectrically active process was found, related to the localized fluctuations within RAF. Moreover, the amount of RAF in EP/T-LDH was reaching up to 40 wt % of the system, whereas in EP/BNP it ranged between 1-7 wt %. In the latter case the presence of NPs was found to simultaneously increase and decrease the number of mobile segments, due to the interphase formation and changes in crosslinking density. The difference between the two systems was ascribed to the presence of additional amine functionalities in the T-LDH nanofiller. Second, employing BDS and SHS, a systematic study on the effect of NPs on the segmental dynamics was performed. For example, depending on the nanofiller, the α-processes related to regions with higher crosslinking density was found to shift to higher and lower temperatures with increasing T-LDH and BNPs concentration, respectively. The observed difference is due to the different synergism of the polymer matrix with the nanofiller. Third, a detailed investigation of the vitrification kinetics was performed with DSC and FSC. The concentration dependence of the glass transition temperature was found, similar to the behavior of the α-processes. It was shown that, in parallel to the detected main glass transition, epoxy-based materials can exhibit an additional low temperature vitrification mechanism. As expected from the two distinct α-processes, this behavior was however not discussed in prior studies for an unfilled network former. This finding was correlated to the structural heterogeneity evidenced by other techniques. This thesis, dealing with an in-depth research on the epoxy-based materials that are already successfully employed in numerous applications underlines the necessity of more fundamental research in this field. It shines light on the complexity of these systems and contributes to defining how the structure-property relationships can be determined by combining multiple experimental techniques and analytical methodology. T2 - PhD defense CY - Online meeting DA - 18.12.2020 KW - Interfaces KW - Nanocomposites KW - Rigid amorphous fraction KW - TMDSC KW - BDS PY - 2020 AN - OPUS4-52035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Omar, Hassan A1 - Qu, Xintong A1 - Schönhals, Andreas T1 - Resolving the mystery of the molecular dynamics of epoxy-based materials using broadband dielectric spectroscopy and hypheneated calorimetry N2 - A detailed calorimetric and dielectric study on two epoxy-based nanocomposite system was performed employing bisphenol A diglycidyl ether (DGEBA) cured with diethylenetriamine (DETA) and methyl tetrahydrophtalic acid anhydride (MTHPA) aas the polymer matrix and taurine-modified MgAL layered double hydroxide (T-LDH) and boehmite as nanofiller. The molecular dynamics investigation revealed an intrinsic structural heterogeneity of the epoxy materials. Moreover the polymer/particle interphase was qualitatively and quantitavely investigated. T2 - Online International Dielectric Society 2020 Workshop CY - Online meeting DA - 28.09.2020 KW - Interfaces KW - Nanocomposites KW - Rigid amorphous fraction KW - BDS KW - TMDSC PY - 2020 AN - OPUS4-51492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina T1 - Flash DSC investigations on nanocomposites and electrospun fibers containing nanoparticles N2 - It was found for inorganic/polymer nanocomposites that a so-called Rigid Amorphous Phase (RAF) is formed in the interfacial region by adsorption of polymer segments onto the nanoparticles. The segmental dynamics of RAF is expected to be altered, as compared to the pure matrix, which might percolate into the entire system, affecting the overall nanocomposite properties. Here, the structure and molecular mobility of epoxy-based PNCs with different nanofillers (layered double hydroxide and boehmite) was studied by a combination of calorimetric and X-Ray scattering techniques. Temperature modulated DSC (TMDSC) showed that depending on the nanofiller, RAF can reach up to 40 wt % of the system or, on the contrary, the overall mobility of the matrix might increase due to the presence of particles. Such contrasting results, including the high amount of RAF, which was never shown before for epoxy-based PNCs, emphasize the importance of interfaces. Additionally, glass transition and glassy dynamics were investigated by a novel technique, Flash DSC (heating rates up to 10 kK/s) employed for the first time to a thermosetting system and electrospun fibers, which did not result in their degradation. It was used to study both the vitrification kinetics and glassy dynamics of the PNCs, for instance further confirming the presence of RAF and its impact on the overall material properties. T2 - 4th Mettler Toledo Flash DSC conference CY - Zurich, Switzerland DA - 25.11.2019 KW - Flash DSC KW - Nanocomposites KW - Rigid amorphous fraction KW - TMDSC KW - BDS KW - Boehmite KW - Electrospun fibers PY - 2019 AN - OPUS4-50067 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas A1 - Madkour, Sherif A1 - Gawek, Marcel A1 - Szymoniak, Paulina A1 - Hertwig, Andreas T1 - Growth Kinetics and molecular mobility of irreversibly adsorbed layers in thin Polymer films investigated by Nanosized relaxation spectroscopy and complimentary methods N2 - In well-annealed thin polymer films, with non-repulsive polymer/substrate interactions, an irreversibly adsorbed layer is expected to from. These adsorbed layers have shown greate potential for technological applications. However, their growth kinetics and molecular dynamics are still not fully understood. This is partly due to the hard accessibility of these layers in thin films. Here, the irreversibly adsorbed layers of homopolymer thin films are revealed by solvent-leaching experiments. First, the growth kinetics of these layers is investigated as a function of annealing time, annealing temperature, leaching time and the original filme thickness. The film thickness, topography and the quality of the adsorbed layer is controlled by Atomic Force Microscopy (AFM). Secondly, the molecular mobility of the adsorbed layer is investigated by Broadband Dielectric Spectroscopy (BDS). A recently developed nanostructured capacitor arrangement is employed to measure the layer with a free surface. The results are quantitatively compared and discussed with respect to recently published work. T2 - Polymers on the nanoscale CY - Princeton, New Jersey, USA DA - 31.10.2019 KW - Thin polymer films PY - 2019 AN - OPUS4-49559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Pauw, Brian Richard A1 - Szymoniak, Paulina T1 - Dataset and Jupyter worksheet interpreting the (results from) small- and wide-angle scattering data from a series of boehmite/epoxy nanocomposites. Accompanies the publication "Competition of nanoparticle-induced mobilization and immobilization effects on segmental dynamics of an epoxy-based nanocomposite" N2 - Dataset and Jupyter worksheet interpreting the (results from) small- and wide-angle scattering data from a series of boehmite/epoxy nanocomposites. Accompanies the publication "Competition of nanoparticle-induced mobilization and immobilization effects on segmental dynamics of an epoxy-based nanocomposite", by Paulina Szymoniak, Brian R. Pauw, Xintong Qu, and Andreas Schönhals. Datasets are in three-column ascii (processed and azimuthally averaged data) from a Xenocs NanoInXider SW instrument. Monte-Carlo analyses were performed using McSAS 1.3.1, other analyses are in the Python 3.7 worksheet. Graphics and result tables are output by the worksheet. KW - Small angle scattering KW - X-ray scattering KW - Nanocomposite KW - Polymer nanocomposite KW - Boehmite KW - Analysis KW - SAXS/WAXS PY - 2020 DO - https://doi.org/10.5281/zenodo.4321087 PB - Zenodo CY - Geneva AN - OPUS4-51829 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Leng, Jing A1 - Szymoniak, Paulina A1 - Kang, N.-J. A1 - Wang, D-Y A1 - Wurm, A. A1 - Schick, C. A1 - Schönhals, Andreas T1 - Influence of interfaces on the crystallization behavior and the rigid amorphous phase of poly(l-lactide)-based nanocomposites with different layered doubled hydroxides as nanofiller N2 - Based on the three-phase model of semi-crystalline polymers, we determined all phase fractions of the NiAl-LDH/PLLA nanocomposites in dependence on the concentration of the nanofiller. Moreover, the rigid amorphous fraction (RAF) was separated into the RAFcrystal and the RAFfiller unbiasedly. A detailed comparison to the related nanocomposite system MgAl-LDH/PLLA was made considering that Mg and Ni have different atomic weights. As a first result is was found that NiAl-LDH/PLLA displays a higher crystallization rate compared to MgAl-LDH/PLLA, which is related to the different morphologies of the two nanocomposite systems. For both systems RAFcrystal increases with increasing concentration of the nanofiller. This means in the case of the nanocomposite not each crystal produces the same amount of RAF, as often assumed. Also, RAFfiller increases with the concentration for both systems but in a different way. This is discussed considering again the different morphologies of both nanocomposites. KW - Polymer-based nanocomposites KW - Temperature modulated differential scanning calorimetry PY - 2019 DO - https://doi.org/10.1016/j.polymer.2019.121929 VL - 184 SP - 121929 PB - Elesevier Ltd. AN - OPUS4-49557 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Kolmangadi, Mohamed A. A1 - Juranyi, Fanni A1 - Böhning, Martin A1 - Zorn, Reiner A1 - Schönhals, Andreas T1 - Low-Frequency Vibrational Density of State of Janus-Polynorbornenes: The Dependence of the Boson Peak on the Nanophase-Separated Structure N2 - Inelastic incoherent neutron time-of-flight scattering was employed to investigate the low-frequency vibrational density of states (VDOSs) for a series of glassy Janus-poly(tricyclononenes), which consist of a rigid main chain and flexible alkyl side chains. Here, the length of the flexible side chains was systematically varied from propyl to octyl. Such materials have potential applications as active separation layers in gas separation membranes as a green future technology, especially for the separation of higher hydrocarbons. From the morphological point of view, the Janus polynorbornenes undergo a nanophase separation into alkyl side chain-rich nanodomains surrounded by a rigid polynorbornene matrix. Here, the influence of the nanophase-separated structure on the low-frequency VDOS is investigated from a fundamental point of view. The low-frequency VDOSs of these Janus polynorbornene show excess contributions to the Debye type VDOS known as the Boson peak (BP) for all side chain lengths. Due to the high incoherent scattering cross-section of hydrogen, most of the scattering comes from the alkyl side chain-rich domains. Compared to conventional glass-forming materials, in the considered Janus polynorbornenes, the BP has a much lower intensity and its frequency position is shifted to higher values. These experimental results are discussed in terms of the nanophase-separated structure where the alkyl chain-rich domains were constrained by the surrounding matrix dominated by the rigid backbone. With increasing alkyl chain length, the size of the alkyl chain-rich domains increases. The frequency position of the BP shifts linearly to lower frequencies with the size of these nanodomains estimated from X-ray measurements. The obtained results support the sound wave interpretation to the BP KW - Inelastic neutron scattering PY - 2023 DO - https://doi.org/10.1021/acs.macromol.3c00913 SN - 0024-9297 SP - 1 EP - 10 PB - ACS AN - OPUS4-57972 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas A1 - Szymoniak, Paulina A1 - Böhning, Martin A1 - Zorn, R. T1 - Inelastic and Quasielastic Neutron Scattering Experiments on Mircroporous Membranes for Green Separation processes N2 - Polymers with intrinsic microporosity are promising candidates for the active separation layer in gas separation membranes. These polymers are characterized by a high permeability and reasonable permselectivity. The latter point is somehow surprising because for microporous systems a more Knudson-like diffusion is expected then a size dependent temperature activated sieving process. It was argued in the framework of a random gate model that molecular fluctuations on a time scale from ps to ns are responsible for the permselectivity. Her a series of microporous polynorbornenes with bulky Si side groups and a rigid backbone are considered which have different microporosity characterized by BET surface area values. First inelastic time-of-flight neutron scattering measurements were carried out to investigate the low frequency density of state (VDOS). The measured data show the characteristic low frequency excess contribution to the VDOS above the Debye sound wave level, generally known as the Boson peak in glass-forming materials. It was found the maximum position of the Boson peak correlates with the BET surface area value. For two selected comparable polynorbornenes elastic scans as well as QENS measurements by a combination of neutron time-of-flight and backscattering are carried out. A low temperature relaxation process was found for both polymers. This process was assigned to the methyl group rotation. It was analysed in terms of a jump diffusion in a three-fold potential. The analysis of the dependence of the elastic incoherent structure factor on the scattering vector yields the number of methyl groups which might be immobilized. T2 - MLZ Conference 2022: Neutrons for mobility CY - Lengries, Germany DA - 31.05.2022 KW - Polymers of intrinsic Microporosity PY - 2022 AN - OPUS4-55674 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas A1 - Szymoniak, Paulina A1 - Böhning, Martin A1 - Zorn, R. T1 - Inelastic and Quasielastic Neutron Scattering Experiments on Mircroporous Membranes for Green Separation processes N2 - Polymers with intrinsic microporosity are promising candidates for the active separation layer in gas separation membranes. These polymers are characterized by a high permeability and reasonable permselectivity. The reasonable permselectivity of these materials is somehow surprising because for microporous systems a more Knudsen-like diffusion is expected rather than a size dependent temperature activated sieving process. It was argued in the framework of a random gate model that molecular fluctuations on a time scale from ps to ns are responsible for the permselectivity. Here a series of microporous polynorbornenes with bulky SiMe3 side groups and a rigid backbone is considered which have different microporosities characterized by BET surface area values. First inelastic time-of-flight neutron scattering measurements were carried out to investigate the low frequency density of state (VDOS). The measured data show the characteristic low frequency excess contribution to the VDOS above the Debye sound wave level, generally known as the Boson peak in glass-forming materials. It was found that the maximum position of the Boson peak correlates with the BET surface area. For two selected comparable polynorbornenes elastic scans as well as QENS measurements by a combination of neutron time-of-flight and backscattering were carried out. A low temperature relaxation process was found for both polymers. This process was assigned to the methyl group rotation. It was analysed in terms of a jump diffusion in a three-fold potential. The analysis of the dependence of the elastic incoherent structure factor on the scattering vector yields the number of methyl groups which might be immobilized. T2 - QENS / WINS 2022 CY - San Sebastian, Spain DA - 23.05.2022 KW - Polymers of intrinsic Microporosity PY - 2022 AN - OPUS4-55673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Omar, Hassan A1 - Gawek, Marcel A1 - Hertwik, Andreas A1 - Madkour, Sherif A1 - Schönhals, Andreas T1 - Investigation of the behavior of thin polymeric films including the adsorbed layer on the substrate by nano-sized relaxation spectroscopy and complementary methods N2 - Thin polymeric films are of great importance of high number of high-tech applications for instance in sensors and nanoelectronics. Form the scientific point of view thin films with thickness below 100 nm are ideal model systems to study confinement effects on its properties for instance on the molecular relaxation processes. In this contribution an overview is presented about the behavior of different systems as investigated by nanosized relaxation spectroscopy like broadband dielectric spectroscopy employing nano structured capacitors and AC chip calorimetry complimented by ellipsometry. The systems considered are PVME1, PVME/PS blends2,3 P2VP4, PBAC5 and polysulfone6. Besides the film also the adsorbed layer on the substrate prepared by a leaching approach and investigated by AFM is considered.1,4-7. For these investigationsss it is found that the adsorbed layer itself exhibits a relaxation dynamics which might be assigned either to molecular motions or to adsorptions desorption kinetics. T2 - 9. International Discussion Meeting Relaxation Complex Systems CY - Chiba, Japan DA - 12.08.2023 KW - Thin polymer films PY - 2023 AN - OPUS4-58103 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Omar, Hassan A1 - Szymoniak, Paulina A1 - Hertwig, Andreas A1 - Schönhals, Andreas T1 - Invesitgation of Thin Film Interactions with Inorganic Surfaces N2 - Thin polymer films are of vital importance due to their low production costs and wide range of applications in sensors, electronics, and coatings. Their geometry is ideal for the study of confinement effects, specifically one-dimensional confinement, on the thermodynamic properties and segmental dynamics of polymers. For this investigation, films of PC are prepared on both glass and silica substrates to measure the dielectric and calorimetric behavior as a function of film thickness. The methodology consists of broadband dielectric spectroscopy (BDS), ellipsometry, and atomic force microscopy (AFM). Using ellipsometry, the glass transition shows an increase with decreasing film thickness. Compared to a previous investigation of PC where dilatometry was used, an increase in PC was seen, but now only at thicknesses below 20 nm. Therefore, the critical thickness of PC, where the bulk-like layer no longer percolates through the film, is dependent on the method probing the glass transition. The dielectric behavior shows a deviation from bulk behavior with decreasing film thickness, although still showing a Vogel-Fulcher-Tammann (VFT) temperature dependence for all films. The influence of the adsorbed layer on the molecular mobility was also addressed. T2 - Deutschen Physikalische Gesellschaft (DPG) Tagung CY - Regensburg, Germany DA - 04.09.2022 KW - Thin films KW - Adsorbed Layer KW - Broadband dielectric spectroscopy PY - 2022 AN - OPUS4-55706 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Omar, Hassan A1 - Szymoniak, Paulina A1 - Hertwig, Andreas A1 - Schönhals, Andreas T1 - Growth Kinetics and Molecular Mobility of the Adsorbed Layer of Poly(bisphenol-A Carbonate) (PBAC), Polysulfone (PSU), and Poly (2-Vinyl Pyridine) (P2VP) N2 - Interactions between a polymer and a substrate interface play a vital role in understanding the improvement in thin film material properties as well as serving as a model for nanocomposites. For any non-repulsive polymer-substrate interactions, polymer segments form an irreversibly adsorbed layer and show a slowdown in the glassy dynamics and thus an increase in the thermal glass transition temperature compared to the bulk-like values. The growth kinetics of the adsorbed layer obey a two-step mechanism: formation of immobilized layer with flat segmental conformations and a loosely bound layer with stretched chains pinned to the surface. Here the adsorbed layer was studied for: poly (bisphenol-A carbonate) (PBAC) and polysulfone (PSU), two bulky polymers containing a functional group (phenyl ring) in the backbone and compared to poly (2-vinyl pyridine) (P2VP), where the backbone is a vinyl-derivative and the functional group (pyridine) is in the side chain. The growth kinetics for PBAC and PSU were found to deviate from the well-known mechanism, observed for polymers such as P2VP. Atomic force microscopy and ellipsometry were used for this investigation and was additionally supported by broadband dielectric spectroscopy. T2 - 11th International Conference on Times of Polymers (TOP) and Composites CY - Ischia, Italy DA - 11.06.2023 KW - Adsorbed Layer KW - Dielectric Spectroscopy KW - Atomic Force Microscopy KW - Ellipsometry KW - Growth Kinetics KW - Molecular Mobility PY - 2023 AN - OPUS4-57709 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolmangadi, Mohamed Aejaz A1 - Szymoniak, Paulina A1 - Schönhals, Andreas A1 - Smales, Glen Jacob A1 - Böhning, Martin T1 - Molecular Dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase separation N2 - We report the dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbone and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl). Dielectric dispersion reveals two active processes at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter relates to the glassy dynamics of the flexible -Si(OR)3 side groups, that creates a nanophase separation in both the alkyl chain rich and backbone rich domains. Temperature modulated DSC measurements and X-ray scattering experiment confirm the nanophase separation. Fast Scanning Calorimetry employing both fast heating and cooling rates detects the glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC. The cooperative length scale of glass transition and the size of the alkyl chain rich domains increases with chain length. Alongside these results, a significant conductivity contribution was observed for all Poly(tricyclononenes) with Si(OR)3 side groups, which is interpreted in terms of a percolation model. T2 - Chemical Engg Seminar CY - Columbia University, NY, USA DA - 14.03.2023 KW - Glass transition KW - Conductivity KW - Fast Scanning Calorimetry KW - Dynamics PY - 2023 AN - OPUS4-57343 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Kolmangadi, Mohamed A1 - Schönhals, Andreas T1 - Molecular Dynamics of nNanophase-Separated Janus Polynorbornenes for gas separation N2 - Janus polytricyclononenes (PTCN) with rigid backbones and flexible n-alkyl (n = propyl, butyl, hexyl, octyl, decyl) are novel, innovative materials that show potential in separating hydrocarbons. These superglassy polymers were designed to show an enhanced and controllable gas permeability via flexible alkyl side chains that promote mass transport, as opposed to conventional microporous polymers, where permeability is a function of the free-volume entities. PTCNs, investigated by small angle X-ray scattering (SAXS), show nanophase separation between the n-alkyl side chains and the backbones. The size of the nanodomains increases with the length of the n-alkyl side groups. In addition, for the alkyl chain-rich nanodomains a distinct α-relaxation was found by means of broadband dielectric spectroscopy (BDS) and temperature modulated DSC (TMDSC). The glass transition of the backbone-rich domains, which is beyond or near to the degradation of the materials, was evidenced by fast scanning calorimetry (FSC) by decoupling it from decomposition, employing high heating rates up to 104 K/s. Further, Janus PTCNs were studied by quasielastic neutron scattering (QENS) employing the backscattering IN16B (ILL, Grenoble) and time of flight FOCUS (PSI, Villigen) instruments. For an overview of dynamic processes setting in at different temperatures inelastic (IFWS) and elastic fixed window scans (EFWS) were conducted. IFWS showed that the segmental motions of alkyl-rich nanodomains shift to higher temperatures with increasing alkyl chain length, which agrees with SAXS and BDS findings. For the lowest side chain lengths an additional low temperature relaxation process was found, assigned to methyl group rotations. T2 - IDS 2022 CY - San Sebastian, Spain DA - 03.09.2022 KW - Gas separation KW - Membranes PY - 2022 AN - OPUS4-55899 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Omar, Hassan A1 - Szymoniak, Paulina A1 - Hertwig, Andreas A1 - Schönhals, Andreas T1 - Probing Nanoscale Relaxation Behavior in Thin Polymer Films N2 - The investigations into the complicated effects of film thickness on bulk properties of thin polymer films has yielded conflicting results. The reduction in molecular mobility, and with it an increase in the glass transition temperature, for thin films of poly (bisphenol A carbonate) (PBAC) was assigned to the formation of an adsorbed layer. The adsorbed layer was obtained by washing away the loosely bounded chains using a good solvent. Next, using atomic force microscopy (AFM), the thickness of each sample was measured after annealing for various times at three different annealing temperatures. The growth of this adsorbed layer was shown to deviate from the previously reported 2-step mechanism seen for other polymers. For PBAC, after very long annealing times at high temperatures the thin films were dewetted, where segments of the adsorbed layer were removed from the substrate. T2 - Royal Society of Chemistry (RSC) Poster CY - Online meeting DA - 28.02.2023 KW - Thin films KW - Adsorbed Layer KW - Broadband dielectric spectroscopy KW - Atomic force microscopy KW - Growth Kinetics PY - 2023 AN - OPUS4-57196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lee, Jun-Seob A1 - Radnik, Jörg A1 - Bäßler, Ralph T1 - Passivity of alloy 31 in green-death solution N2 - The passivation behavior of alloy 31 was investigated as a function of passivation potential in a green-death solution at 40 °C. The alloy 31 surface is in a stable passive state during cyclic potentiodynamic polarization. In potentiostatic polarization of alloy 31, passive current density increases with an increase in the passivation potential. Electrochemical impedance spectroscopy (EIS) and Mott–Schottky (M–S) analysis showed that a more defective n-type semiconductive passive film forms as the potential increases. X-ray photoelectron spectroscopy (XPS) revealed that passive film consists of mainly chromium and minor iron and nickel oxides. The increase of the applied potential is considered to be a reason for the change in passive film stability. KW - Passive film KW - Steel KW - Alloy 31 KW - X-ray photoelectron spectroscopy PY - 2018 DO - https://doi.org/10.1002/maco.201709996 SN - 0947-5117 SN - 1521-4176 VL - 69 IS - 9 SP - 1218 EP - 1226 PB - Wiley-VCH CY - Weinheim AN - OPUS4-45938 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lisec, Jan A1 - Recknagel, Sebastian A1 - Prinz, Carsten A1 - Vogel, Kristin A1 - Koch, Matthias A1 - Becker, Roland T1 - eCerto—versatile software for interlaboratory data evaluation and documentation during reference material production N2 - The statistical tool eCerto was developed for the evaluation of measurement data to assign property values and associated uncertainties of reference materials. The analysis is based on collaborative studies of expert laboratories and was implemented using the R software environment. Emphasis was put on comparability of eCerto with SoftCRM, a statistical tool based on the certification strategy of the former Community Bureau of Reference. Additionally, special attention was directed towards easy usability from data collection through processing, archiving, and reporting. While the effects of outlier removal can be flexibly explored, eCerto always retains the original data set and any manipulation such as outlier removal is (graphically and tabularly) documented adequately in the report. As a major reference materials producer, the Bundesanstalt für Materialforschung und -prüfung (BAM) developed and will maintain a tool to meet the needs of modern data processing, documentation requirements, and emerging fields of RM activity. The main features of eCerto are discussed using previously certified reference materials. KW - Reference material KW - Statistics KW - Software KW - Collaborative trial PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591851 DO - https://doi.org/10.1007/s00216-023-05099-3 SP - 1 EP - 9 PB - Springer Science and Business Media LLC AN - OPUS4-59185 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - BOOK A1 - Schönhals, Andreas A1 - Szymoniak, Paulina T1 - Dynamics ooof Composite Materials N2 - Historically, to tune the properties of a polymer or more general soft matter systems by a second phase is not a new concept and dates back to the 40s of the last century. Beside some successes, the improvement of the properties remained somehow limited. The expectations of the enhancement of the properties of composites changed by the developments of Toyota Central research in the 1990s. It was shown that the incorporation of 5 vol% exfoliated layers of a clay system into a polymer leads to a strong improvement of the mechanical and thermal properties. This discovery stimulated a broad research interest of both fundamental and applied character. Today, polymer-based nanocomposites have reached a billion-dollar global market. The corresponding applications span from components for transportation, commodity plastics with enhanced barrier and/or flame retardancy characteristics, to polymers with electrical properties for shielding, electronics, sensors, and solar cells as well as to live science. Important fields are filled rubbers, reinforced thermoplastics, or thermosets for automotive, aircraft/space and marine industries, but also membranes for separation processes as well as barrier layers, just to mention a few. For a variety of applications, the molecular mobility in nanocomposites is of great importance. This concerns the molecular mobility needed to form a percolating filler network in rubbers used in tires or in composites employed in electric shielding applications. In general, it is also essential for processing polymer-based nanocomposites. Furthermore, separation processes in composite materials for membranes require a certain molecular mobility. This also concern nanodielectrics used in electrical applications or sensors where the mobility of charge carriers can be related to the fluctuations of molecular groups etc. Finally, the molecular mobility can be taken as probe for structure on a molecular scale. Broadband dielectric spectroscopy is a powerful tool to investigate the molecular mobility in polymer systems. It is due to the extremely broad frequency and sensitivity range that can be covered by this technique. Information about localized and cooperative molecular fluctuations, polarization effects at interfaces, as well as charge transport processes can be deduced. Therefore, this book focusses on broadband dielectric spectroscopy of composite materials. Moreover, the dielectric studies are accompanied by mechanical spectroscopy, advanced calorimetry, NMR techniques, as well as transmission electron microscopy and X-ray scattering investigations. Besides a brief introduction to (nano)composites, the book aims to address fundamental aspects of the molecular mobility in this innovative group of materials. Selected examples with scientific interest and some cases with high industrial impact were chosen. Due to the breadth of the subject, unfortunately not all topics could be addressed in detail, such as processing for instance. Berlin, Andreas Schönhals July 2021 Paulina Szymoniak KW - Composite materials KW - Nanocomposites PY - 2022 SN - 978-3-030-89722-2 SN - 978-3-030-89723-9 DO - https://doi.org/10.1007/978-3-030-89723-9 VL - 2022 SP - 1 EP - 375 PB - Springer Nature CY - Cham, Switzerland AN - OPUS4-54538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ghasem Zadeh Khorasani, Media A1 - Elert, Anna Maria A1 - Hodoroaba, Vasile-Dan A1 - Agudo Jácome, Leonardo A1 - Altmann, Korinna A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Short- and long-range mechanical and chemical interphases caused by interaction of Boehmite (γ-AlOOH) with anhydride-cured epoxy resins N2 - Understanding the interaction between boehmite and epoxy and the formation of their interphases with different mechanical and chemical structures is crucial to predict and optimize the properties of epoxy-boehmite nanocomposites. Probing the interfacial properties with atomic force microscopy (AFM)-based methods, especially particle-matrix long-range interactions, is challenging. This is due to size limitations of various analytical methods in resolving nanoparticles and their interphases, the overlap of interphases, and the effect of buried particles that prevent the accurate interphase property measurement. Here, we develop a layered model system in which the epoxy is cured in contact with a thin layer of hydrothermally synthesized boehmite. Different microscopy methods are employed to evaluate the interfacial properties. With intermodulation atomic force microscopy (ImAFM) and amplitude dependence force spectroscopy (ADFS), which contain information about stiffness, electrostatic, and van der Waals forces, a soft interphase was detected between the epoxy and boehmite. Surface potential maps obtained by scanning Kelvin probe microscopy (SKPM) revealed another interphase about one order of magnitude larger than the mechanical interphase. The AFM-infrared spectroscopy (AFM-IR) technique reveals that the soft interphase consists of unreacted curing agent. The long-range electrical interphase is attributed to the chemical alteration of the bulk epoxy and the formation of new absorption bands. KW - Nanocomposites KW - Interphase KW - Intermodulation AFM KW - Electron microscopy KW - Infrared nano AFM PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483672 UR - https://www.mdpi.com/2079-4991/9/6/853/htm DO - https://doi.org/10.3390/nano9060853 SN - 2079-4991 VL - 9 IS - 6 SP - 853, 1 EP - 20 PB - MDPI AN - OPUS4-48367 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Gawek, Marcel A1 - Madkour, S. A1 - Schönhals, Andreas T1 - Confinement and localization effects revealed for thin films of the miscible blend Poly(vinyl methyl ether) / Polystyrene with a composition of 25/75 wt% N2 - Thin films (200-7nm) of the asymmetric polymer blend poly(vinyl methyl ether) (PVME)/polystyrene (PS) (25/75wt%) were investigated by broadband dielectric spectroscopy (BDS). Thicker samples ([Formula: see text]37 nm) were measured by crossed electrode capacitors (CEC), where the film is capped between Al-electrodes. For thinner films ([Formula: see text]37 nm) nanostructured capacitors (NSC) were employed, allowing one free surface in the film. The dielectric spectra of the thick films showed three relaxation processes ( [Formula: see text] -, [Formula: see text] - and [Formula: see text] -relaxation), like the bulk, related to PVME fluctuations in local spatial regions with different PS concentrations. The thickness dependence of the [Formula: see text] -process for films measured by CECs proved a spatially heterogeneous structure across the film with a PS-adsorption at the Al-electrodes. On the contrary, for the films measured by NSCs a PVME segregation at the free surface was found, resulting in faster dynamics, compared to the CECs. Moreover, for the thinnest films ([Formula: see text]26 nm) an additional relaxation process was detected. It was assigned to restricted fluctuations of PVME segments within the loosely bounded part of the adsorbed layer, proving that for NSCs a PVME enrichment takes place also at the polymer/substrate interface. KW - Thin polymer films KW - Broadband dielectric spectroscopy PY - 2019 DO - https://doi.org/10.1140/epje/i2019-11870-3 SN - 1292-895X VL - 42 IS - 8 SP - 101, 1 EP - 11 PB - Springer AN - OPUS4-48651 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yin, Huajie A1 - B, Yang A1 - Chua, Y. Z. A1 - Szymoniak, Paulina A1 - Carta, M A1 - Malpass-Evans, R A1 - McKeown, N A1 - Harrison, W A1 - Budd, P A1 - Schick, C A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Effect of backbone rigidity on the glass transition of polymers of in-trinsic microporosity probed by fast scanning calorimetry N2 - Polymers of Intrinsic Microporosity (PIMs) of high performance have developed as materials with a wide application range in gas separation and other energy-related fields. Further optimization and long-term behavior of devices with PIMs require an understanding of the structure-property relationships including physical aging. In this context the glass transi-tion plays a central role, but with conventional thermal analysis a glass transition is usually not detectable for PIMs be-fore their thermal decomposition. Fast scanning calorimetry provides evidence of the glass transition for a series of PIMs, as the time scales responsible for thermal degradation and for the glass transition are decoupled by employing ultrafast heating rates of tens of thousands K s-1. The investigated PIMs were chosen considering the chain rigidity. The estimated glass transition temperatures follow the order of the rigidity of the backbone of the PIMs. KW - Polymers of intrinsic microporosity KW - Fast scanning calormetry PY - 2019 DO - https://doi.org/10.1021/acsmacrolett.9b00482 SN - 2161-1653 VL - 8 IS - 8 SP - 1022 EP - 1028 PB - ACS Publications AN - OPUS4-48617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Heinz A1 - Ghasem Zadeh Khorasani, Media A1 - Silbernagl, Dorothee T1 - Grenzflächen als Material: Konzepte und Beispiele zu nanoverstärkten Duroplasten N2 - Nachdem Jahrzehnte die Grenzfläche zwischen Kohlefaser und Duroplastmatrix optimiert wurde liegt das Augenmerk heute auf der Polymermatrix selbst. Diese lässt sich hinsichtlich ihres Elastizitätsmoduls und ihrer Bruchfestigkeit verbessern, indem Nanopartikel aus Böhmit (AlOOH) eindispergiert werden. Der Vortrag geht auf integrale und hochauflösend-bildgebende Methoden ein die ein Verständnis der komplexen Zusammenhänge ermöglichen. Nach einer chemischen in-situ Analyse des Aushärtvorgangs, aus welchem sich die Bedeutung der externer Parameter ablesen lässt, werden diverse hochauflösende, neue Methoden der Rasterkraftmikroskopie (AFM) eingeführt. Der lokalen Bestimmung des E-Moduls der Nanopartikel folgen Ausführungen zum temperaturabhängigen Chemismus des Böhmits, der während der Aushärtung Wasser freisetzt. Die hochauflösende Bestimmung der Oberflächenpotentiale, der Steifigkeit, der attraktiven Kräfte zwischen Spitze und Probe sowie der Energiedissipation im Kontakt stellen auf der Nanoskala eine komplexe Datenquelle dar, die auf der Makroskala einer Ergänzung bedarf: Durch Kombination von dynamisch-mechanisch-thermischer Analyse einerseits und Kartierung physikalischer Eigenschaften auf der Nanoskala andererseits kann der Zusammenhang zwischen chemischer Steuerung der Netzwerkbildung und den mechanischen Eigenschaften des Nanokomposits geklärt werden. Überraschend ist, dass bei geeigneter Steuerung der lokale E-Modul der Polymermatrix den des Füllstoffs übersteigt. Die Rissfortschrittsenergie wird in Böhmit-modifiziertem Epoxy verbessert absorbiert, die These dazu ist, dass die (010)-Gleitebenen, die nur durch Wasserstoffbrücken zusammen gehalten werden, einigermaßen schadlos geschert werden können. Daraus folgt, dass das System auf der Nanoskala über einen, wenn auch begrenzten, Selbstheilmechanismus verfügt. Zudem wird durch die hohe Heterogenität der Steifigkeit und Energiedissipation des Nanokomposits eine Risstrajektorie vielfach umgelenkt und somit früher gestoppt. Ergebnisse dieses Vortrags stammen aus einer Zusammenarbeit innerhalb des DFG-Forscherverbundes FOR2021 „Wirkprinzipien nanoskaliger Matrixadditive für den Faserverbundleichtbau“. T2 - Niedersächsisches Symposium Materialtechnik - NSM 2019 CY - Clausthal, Germany DA - 14.02.1019 KW - Nanokomposit KW - Böhmit KW - Risstrajektorie KW - Oberflächenpotential KW - Energiedissipation im Kontakt KW - Oberflächensteifigkeit KW - attraktive Wechelwirkung KW - Epoxy-Anhydrid Duroplast KW - Leichtbau PY - 2019 AN - OPUS4-47636 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waniek, Tassilo A1 - Zarinwall, A. A1 - Silbernagl, Dorothee A1 - Garnweitner, G. A1 - Sturm, Heinz T1 - Mechanical coupling of matrix and nanoparticles depending on particle surface modification N2 - Boehmite nanoparticles has been successfully functionalized with APTES. After APTES functionalization further modification with tailored molecules e.g. via carboxylic acids is possible. The tailored surface functionalization is strongly enhanced by improved coupling protocols. Arbitrary variation of the functionalization degree is possible. Thereby the temperature stable APTES functionalization enables a wide range of functional groups. By TGA-MS analysis strong evidence for the bonding situation of the APTES on the boehmite surface has been found. Additionally first experiments has been performed to predict the polymer-particle compatibility enhancement via reverse wetting angle measurements with AFM. T2 - Workshop Acting Principles of Nano-Scaled Matrix Additives for Composite Structures CY - BAM, Berlin, Germany DA - 11.10.2019 KW - Surface modification KW - Nanocomposites KW - Boehmite KW - Silane KW - Thermogravimetry KW - Mass spectrometry PY - 2019 AN - OPUS4-49435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Schönhals, Andreas T1 - Rigid amorphous phase in polymer nanocomposites as revealed by dielectric relaxation spectroscopy and fast scanning calorimetry N2 - For inorganic/polymer nanocomposites a so-called Rigid Amorphous Phase (RAF) is formed in the interfacial region by adsorption of polymer segments onto the nanoparticles. The segmental dynamics of RAF is expected to be altered, as compared to the pure matrix, which might percolate into the entire system, affecting the overall nanocomposite properties. A combination of two relaxation spectroscopy techniques (Broadband Dielectric Spectroscopy (BDS) and Specific Heat Spectroscopy (SHS) in a form of Temperature Modulated DSC (TMDSC)) as well as Fast Scanning Calorimetry (FSC) was employed to investigate the structure and molecular mobility of nanocomposites based on Epoxy and Layered Doubled Hydroxides with different nanoparticle content. First, BDS investigations proved the existence of a process, which is present only for nanocomposites, assigned to the dynamics of polymer segments within RAF. Second, the amount of RAF was quantified by analyzing the change of specific heat capacity step of nanocomposites, comparing to the pure material. Thirdly, the glass transition of nanocomposites was studied with FSC, applying high heating rates (500-10 000 K/s). Considering that all techniques probe essentially the same molecular process, an activation plot was constructed, delivering a complete picture of the molecular mobility and structure of the polymer nanocomposites including RAF. T2 - American Physical Society (APS) March Meeting 2019 CY - Boston, MA, USA DA - 04.03.2019 KW - Nanocomposites KW - Rigid amorphous fraction PY - 2019 AN - OPUS4-47564 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Schönhals, Andreas T1 - Rigid Amorphous Phase in Epoxy-based Nanocomposites as Revealed by Dielectric Spectroscopy and Fast Scanning Calorimetry N2 - For inorganic/polymer nanocomposites a so-called Rigid Amorphous Phase (RAF) is formed in the interfacial region by adsorption of polymer segments onto the nanoparticles. The segmental dynamics of RAF is expected to be altered, as compared to the pure matrix, which might percolate to the entire system, affecting the overall nanocomposite properties. A combination of two relaxation spectroscopy techniques (Broadband Dielectric Spectroscopy (BDS) and Temperature Modulated DSC (TMDSC)) as well as Fast Scanning Calorimetry (FSC) was employed to investigate the structure and molecular mobility of nanocomposites based on Epoxy and Layered Doubled Hydroxides with different nanoparticle content. First, BDS investigations proved the existence of a process, which is present only for nanocomposites, assigned to the dynamics of polymer segments within RAF. Second, the amount of RAF was quantified by analyzing the change of specific heat capacity step of nanocomposites, comparing to the pure material. Thirdly, the glass transition of nanocomposites was studied with FSC, applying high heating rates (0.5-10 kK/s). Considering that all techniques probe essentially the same molecular process, an activation plot was constructed, delivering a complete picture of the molecular mobility and structure of the polymer nanocomposites including RAF. T2 - DPG-Frühjahrstagung 2019 CY - Regensburg, Germany DA - 01.04.2019 KW - Rigid amorphous fraction KW - Nanocomposites PY - 2019 AN - OPUS4-47762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Schönhals, Andreas A1 - Madkour, Sherif T1 - Multiple Glassy Dynamics of an Asymmetric PVME/PS Blend Investigated by Broadband Dielectric and Specific Heat Spectroscopy N2 - Over the past decades research on the molecular dynamics of miscible polymer blends is of topical interest in the literature, to understand the segmental mobility of individual components, as it is affected by blending. In general, miscible polymer blends exhibit a complex dynamic behavior. For an A/B blend the relaxation times of component A and component B are affected by the spatial local compositional heterogeneity, present in binary systems on a microscopic level, regardless of the macroscopic homogeneity. Here, a combination of broadband dielectric and specific heat spectroscopy was employed to study the dynamically asymmetric PVME/PS blend with seven different compositions, focusing on samples with high PS contents. Considering that PS is dielectrically invisible, BDS is a powerful technique to study the response of PVME, as it is affected by PS segments. Here, three separate relaxation processes were found by dielectric investigations, related to confined or constrained PVME segments due to the spatial local compositional heterogeneities, which is in contrary to the previous literature findings [1]. Moreover, the dielectric data was compared with results obtained by specific heat spectroscopy, where a fourth relaxation process was found, due to the cooperative fluctuations of PVME and PS. [1] Colmenero, J., Arbe, A. Soft Matter, 2007, 3, 1474. T2 - DPG-Frühjahrstagung 2019 CY - Regensburg, Germany DA - 01.04.2019 KW - Specific heat spectroscopy KW - Polymer blends KW - Dielectric spectroscopy PY - 2019 AN - OPUS4-47764 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zorn, R. A1 - Szymoniak, Paulina A1 - Kolmangadi, Mohamed Aejaz A1 - Malpass-Evans, R. A1 - McKeown, N. A1 - Jalarvo, N. A1 - Tyagi, M. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Microscopic molecular mobility of high-performance polymers of intrinsic microporosity revealed by neutron scattering – bend fluctuations and signature of methyl group rotation N2 - Polymers of intrinsic microporosity exhibit a combination of high gas permeability and reasonable permselectivity, which makes them attractive candidates for gas separation membrane materials. The diffusional selective gas transport properties are connected to the molecular mobility of these polymers in the condensed state. Incoherent quasielastic neutron scattering was carried out on two polymers of intrinsic microporosity, PIM-EA-TB(CH3) and its demethylated counterpart PIM-EA-TB(H2), which have high Brunauer–Emmett–Teller surface area values of 1030 m2 g-1 and 836 m2 g-1, respectively. As these two polymers only differ in the presence of two methyl groups at the ethanoanthracene unit, the effect of methyl group rotation can be investigated solely. To cover a broad dynamic range, neutron time-of-flight was combined with neutron backscattering. The demethylated PIM-EA-TB(H2) exhibits a relaxation process with a weak intensity at short times. As the backbone is rigid and stiff this process was assigned to bendand-flex fluctuations. This process was also observed for the PIM-EA-TB(CH3). A further relaxation process is found for PIM-EA-TB(CH3), which is the methyl group rotation. It was analyzed by a jump-diffusion in a three-fold potential considering also the fact that only a fraction of the present hydrogens in PIM-EATB(CH3) participate in the methyl group rotation. This analysis can quantitatively describe the q dependence of the elastic incoherent structure factor. Furthermore, a relaxation time for the methyl group rotation can be extracted. A high activation energy of 35 kJ mol-1 was deduced. This high activation energy evidences a strong hindrance of the methyl group rotation in the bridged PIM-EA-TB(CH3) structure. KW - Polymers of Intrinsic Microporosity KW - Neutron Scattering PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604114 DO - https://doi.org/10.1039/d4sm00520a SP - 1 EP - 11 PB - RSC AN - OPUS4-60411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yildirim, Arda A1 - Szymoniak, Paulina A1 - Sentker, K. A1 - Butschies, M. A1 - Bühlmeyer, A. A1 - Huber, P. A1 - Laschat, S. A1 - Schönhals, Andreas T1 - Dynamics and ionic conductivity of ionic liquid crystals forming a hexagonal columnar mesophase N2 - For the first time, the molecular mobility of two linear-shaped tetramethylated guanidinium triflate ionic liquid crystals (ILCs) having different length of alkyl chains were investigated by a combination of broadband dielectric spectroscopy (BDS) and specific heat spectroscopy (SHS). By self-assembly, these ILCs can form a hexagonal ordered mesophase besides plastic crystalline phases and the isotropic state. Three dielectric active processes were found by BDS for both samples. At low temperatures, a γ-process in the plastic crystalline state is observed which is assigned to localized fluctuations of methyl groups including nitrogen atoms in the guanidinium head. At higher temperatures but still in the plastic crystalline state, an α1-process takes place. An α2 process was detected by SHS but with a completely different temperature dependence of the relaxation times than that of the α1-relaxation. This result is discussed in detail, and different molecular assignments of the processes are suggested. At even higher temperatures, electrical conductivity is detected and an increase in the DC conductivity by four orders of magnitude at the phase transition from the plastic crystalline to the hexagonal columnar mesophase is found. This result is traced to a change in the charge transport mechanism from a delocalized electron hopping in the stacked aromatic systems (in the plastic phase) to one dominated by an ionic conduction in the quasi-1D ion channels formed along the supermolecular columns in the ILCs hexagonal mesophases. KW - Ionic liquid crystalls PY - 2018 DO - https://doi.org/10.1039/c7cp08186c SN - 1463-9084 SN - 1463-9076 VL - 20 IS - 8 SP - 5626 EP - 5635 PB - Royal Society of Chemistry AN - OPUS4-44254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Madkour, Sherif A1 - Schönhals, Andreas T1 - Unexpected behavior of thin PVME/PS blend films investigated by specific heat spectroscopy N2 - The structure and molecular dynamics of thin polymer films are of topical interest of soft matter-physics. Commonly, spatial structural heterogeneities of 1D confined thin films (surface, bulk-like and adsorbed layer), are expected to alter the glassy dynamics, compared to the bulk. Here, Specific Heat Spectroscopy (SHS) was used, to investigate the glassy dynamics of thin films of an asymmetric miscible PVME/PS 25/75 wt% blend. SHS measurements showed a non-monotonous thickness dependence of the dynamic Tg, on the contrary to the previously investigated PVME/PS 50/50 wt%. For PVME/PS 25/75 wt% thin films (> 30 nm), due to the presence of PVME-rich adsorbed and surface layers, the bulk-like layer experienced a thickness dependent increase of PS concentration. This led to a systematic increase of dynamic Tg. Further decrease of the film thickness (< 30 nm), resulted in a decrease of dynamic Tg, ascribed to the influence of the surface layer, which has a high molecular mobility. This is the first study, which shows deviations of dynamic Tg of thin films, compared to the bulk, resulting from the counterbalance of the free surface and adsorbed layer. T2 - Spring Meeting of German Physical Society CY - Berlin, Germany DA - 12.03.2018 KW - Thin polymeric films PY - 2018 AN - OPUS4-44494 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas A1 - Madkour, Sherif A1 - Szymoniak, Paulina T1 - Unraveling the dynamics of thin films of a miscible PVME/PS blend N2 - Dielectric spectroscopy (BDS) was employed to investigate the dynamics of thin films (7 – 200 nm) of a Poly (vinyl methyl ether) (PVME) / Polystyrene (PS) blend (50:50 wt%). For the BDS measurements Nano-Structured Capacitors (NSC) were employed, where films have a free surface. This method was applied for film thicknesses up to 36 nm. Thicker films were prepared between Crossed Electrodes Capacitors (CEC). The spectra of the films showed multiple processes. The first process was assigned to the -relaxation of a bulk-like layer. For films measured by NSC, its rates were higher compared to that of the bulk blend. This behavior was related to a PVME-rich free-surface layer. A second process was observed for films measured by CEC (process X) and the 36 nm film measured by NSC (process X2). This process was assigned to fluctuations of PVME constraint by PS. Its activation energy was found to be thickness dependent, due to the evidenced thickness dependency of the compositional heterogeneity. Finally, a third process with an activated temperature-dependence was observed for all films measured by NSC (process X1). It resembled the molecular fluctuations in an adsorbed layer found for films of pure PVME. T2 - Anual Meeting of the American Physical Society CY - Los Angeles, CA, USA DA - 05.03.2018 KW - Thin polymeric films PY - 2018 AN - OPUS4-44414 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Madkour, Sherif A1 - Schönhals, Andreas T1 - Dynamics of nanoscopically confined PVME in thin films of an asymmetric PVME/PS blend N2 - In recent years, substantial efforts have been devoted to investigating nanoscopic confinement of polymers, and its effect on glassy dynamics. Broadband Dielectric Spectroscopy (BDS) was used to study the dynamics of ultra-thin films of PVME/PS 50/50 wt% blend, employing a novel nano-structured capacitor sample arrangement. The investigated system shows a complex dynamic behavior. First, an α-relaxation, related to a bulk-like layer was found. Second, an α’-relaxation was observed, characteristic for dynamically asymmetric blends, where the out of equilibrium dynamics is attributed to weakly-cooperative PVME segments relaxing within a frozen environment of PS segments. Thirdly, for thinnest films, an Arrhenius-like process was dominant in the dielectric spectra, indicating localized fluctuations of the segments. Relaxation rates of this process resembled that of the degenerated α-relaxation of the adsorbed layer, found for pure PVME, thus it was assigned accordingly. For thinnest films, this process undergoes a further confinement, due to the topological constraints, introduced by PS. Such multiple confinement effect has not been reported for ultra-thin films of polymer blends, before this study. T2 - Spring Meeting of German Physical Society CY - Berlin, Germany DA - 12.03.2018 KW - Thin polymeric films PY - 2018 AN - OPUS4-44502 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Silbernagl, Dorothee A1 - Sturm, Heinz A1 - Ghasem Zadeh Khorasani, Media A1 - Schönhals, Andreas T1 - Competition of mobilization and immobilization effects of segmental dynamics in epoxy/Boehmite nanocomposites N2 - The polymer matrix region near a filler surface, termed as the interface, witnessed increasing interest, due to its possible influence on the macroscopic properties of the nanocomposite. The interphase is expecting to have different segmental dynamic, as compared to the pure matrix, which can percolate into the entire system. Here, the segmental dynamics of epoxy/Boehmite nanocomposite was studied by Broadband Dielectric Spectroscopy. It was found that an artificial relaxation process is present in the nanocomposite, on the contrary to the pure epoxy system. It was assigned to constrained fluctuations of polymer chains in the interfacial region, due to the nanofiller. However, the overall dynamic Tg of the system decreased with increasing filler concentration, indicating higher segmental mobility. This was in accordance with Temperature Modulated DSC investigations of specific heat capacity of the system, which was found to increase with increasing filler concentration, up to 10 wt%, indicating increasing mobility of the polymer matrix segments. Surprisingly, for the highest filler content, the heat capacity decreases, implying a formation of an immobilized rigid amorphous phase in the interfacial region. T2 - Spring Meeting of German Physical Society CY - Berlin, Germany DA - 12.03.2018 KW - Nanocomposites PY - 2018 AN - OPUS4-44503 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Schönhals, Andreas A1 - Böhning, Martin A1 - Szymoniak, Paulina ED - Schönhals, Andreas ED - Szymoniak, Paulina T1 - (Nano)Composite Materials—An Introduction N2 - The chapter gives a brief introduction to (nano)compositecomposite materials having the focus on polymer-based nanocomposites. The different dimensionalities of nanoparticles are introduced, along with their distribution in the matrix. Different application fields of polymer-based nanocomposites, like flame retardancy, filled rubbers, nanofilled thermosets and thermoplastics, separation membranes and nanodielectrics, are considered in greater detail. KW - Polymer-based nanocomposites KW - Nanoparticle KW - Distribution of nanoparticles KW - Filled rubbers KW - Filled thermosets and plastics KW - Separation membranes KW - Nanodielectrics PY - 2022 DO - https://doi.org/10.1007/978-3-030-89723-9_1 SP - 1 EP - 31 PB - Springer CY - Cham, Switzerland AN - OPUS4-54565 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Szymoniak, Paulina A1 - Schönhals, Andreas ED - Schönhals, Andreas ED - Szymoniak, Paulina T1 - Epoxy-Based Nanocomposites—What Can Be Learned from Dielectric and Calorimetric Investigations? N2 - Epoxy-based nanocomposites are promisingmaterials for industrial applications (i.e., aerospace, marine, and automotive industries) due to their extraordinary mechanical and thermal properties. Regardless of the broad field of applications, there is still a considerable need to identify their structure–property relationships. Here, a detailed dielectric and calorimetric (DSC and fast scanning calorimetry) study on different epoxy-based nanocomposites was performed. Bisphenol A diglycidyl ether (DGEBA) cured with diethylenetriamine (DETA) was employed as the polymeric matrix, which was reinforced with three diverse nanofillers that exhibit different interaction strengths with the epoxy matrix (halloysite nanotubes, surface modified halloysite nanotubes, and taurine-modified layered double hydroxide). The structure, molecular mobility, and vitrification behavior are discussed in detail, focusing on the intrinsic structural and dynamic heterogeneity, as well as interfacial properties. KW - Nanocomposites KW - Epoxi nanocomposites KW - Dynamics KW - Interphase KW - Ridis amorphous fraction KW - Dielectric spectroscopy KW - Flash DSC KW - Temparatur modulated Flash DSC KW - Temperature modulated DSC PY - 2022 DO - https://doi.org/10.1007/978-3-030-89723-9_11 SP - 335 EP - 367 PB - Springer CY - Cham, Switzerland AN - OPUS4-54566 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas A1 - Yin, Huajie A1 - Kolmangadi, Mohamed Aejaz A1 - Emamverdi, Farnaz A1 - Zorn, R. A1 - Szymoniak, Paulina A1 - Böhning, Martin T1 - Physical investigations on Super glassy Polymers having possible applications in gas Separation Membranes N2 - The properties of polymers of intrinsic microporosity were investigated by fast scanning calorimetry, dielectric spectroscopy and neutron scattering T2 - University of Pennsylvania CY - Online meeting DA - 25.01.2021 KW - Polymer of intrisic microporosity PY - 2021 AN - OPUS4-52065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Omar, Hassan A1 - Schönhals, Andreas A1 - Qu, Xintong T1 - Spatial Inhomogeneity, Interfaces and Complex Vitrification Behavior of Epoxy-based Materials by Broadband Dielectric Spectroscopy and Calorimetry N2 - Although in the last decades epoxy-based nanocomposites have been successfully adopted by the marine, automotive and aerospace industries they are still rarely studied on a fundamental level. This work deals with an in-depth comparative investigation of the structure, molecular mobility and vitrification kinetics of three bisphenol A diglycidyl ether (DGEBA)-based materials with different nanofillers: I) taurine-modified layered double hydroxide (T-LDH), II) boehmite (BNPs) and III) halloysite nanotubes (HNTs). Moreover, the effect of different hardeners (diethylene triamine and methyl tetrahydrophtalic acid anhydride) on the unfilled epoxy matrix is addressed as well. The chosen methodology comprises I) small – and wide – angle X-ray scattering (SAXS/WAXS) II) calorimetry in the forms of a) conventional DSC and b) static fast scanning calorimetry (FSC), III) broadband dielectric spectroscopy (BDS), as well as IV) specific heat spectroscopy in the forms of a) temperature modulated DSC, and b) temperature modulated FSC. The combination of these techniques proved an intrinsic spatial heterogeneity of epoxy-based materials, evidenced by two separate segmental relaxation processes. Although, depending on the hardener the response of the systems to calorimetric and dielectric investigations was different, in a broader sense similar conclusions can be extracted on the structural heterogeneity. As expected from the two distinct α-processes, it was shown that, in parallel to the main glass transition, epoxy-based materials can exhibit an additional low temperature vitrification mechanism, which was not discussed in prior studies for an unfilled network former. Furthermore, the interfacial region (so-called rigid amorphous fraction) was qualitatively and quantitatively addressed, in dependence of the employed nanofiller structure. T2 - Webinar University of Southern Denmark CY - Online meeting DA - 20.01.2021 KW - BDS KW - Nanocomposites KW - Epoxy KW - Rigid amorphous fraction KW - TMDSC KW - Flash DSC PY - 2021 AN - OPUS4-52036 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolmangadi, Mohamed Aejaz A1 - Schönhals, Andreas A1 - Szymoniak, Paulina A1 - Smales, Glen Jacob A1 - Böhning, Martin T1 - Molecular dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase separation N2 - We report the dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbone and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl). Dielectric dispersion reveals two active processes at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter relates to the glassy dynamics of the flexible -Si(OR)3 side groups, that creates a nanophase separation in both the alkyl chain rich and backbone rich domains. Temperature modulated DSC measurements and X-ray scattering experiment confirm the nanophase separation. Fast Scanning Calorimetry employing both fast heating and cooling rates detects the glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC. The cooperative length scale of glass transition and the size of the alkyl chain rich domains increases with chain length. Alongside these results, a significant conductivity contribution was observed for all Poly(tricyclononenes) with Si(OR)3 side groups, which is interpreted in terms of a percolation model. T2 - IDS Online conference 2021 CY - Online meeting DA - 06.09.2021 KW - Glass transition KW - Conductivity KW - Dynamics KW - Fast Scanning Calorimetry PY - 2021 AN - OPUS4-53299 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Szymoniak, Paulina A1 - Omar, Hassan A1 - Schönhals, Andreas T1 - Spatial Inhomogeneity, Interfaces and Complex Vitrification Behavior of Epoxy-based Materials N2 - This work deals with an in-depth comparative investigation of the structure, molecular mobility and vitrification kinetics of three bisphenol A diglycidyl ether (DGEBA)-based materials with different nanofillers: taurine-modified layered double hydroxide (T-LDH) and halloysite nanotubes (HNTs). The chosen methodology comprises I) small – and wide – angle X-ray scattering (SAXS/WAXS) II) calorimetry in the forms of a) conventional DSC and b) static fast scanning calorimetry (FSC), III) broadband dielectric spectroscopy (BDS), as well as IV) specific heat spectroscopy in the forms of a) temperature modulated DSC, and b) temperature modulated FSC. T2 - Abteilungsseminar 6. - FB 6.6 CY - Online meeting DA - 06.05.2021 KW - Broadband dielectric spectroscopy KW - Epoxy nanocomposites KW - Halloysite nanotubes KW - X-ray scattering KW - Differential scanning calorimetry KW - Rigid amorphous fraction KW - Flash DSC PY - 2021 AN - OPUS4-52697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg A1 - Gawek, M. A1 - Madkour, S. A1 - Szymoniak, Paulina A1 - Omar, Hassan A1 - Schönhals, Andreas T1 - Energy-resolved x-ray photoelectron spectroscopy measurements on the concentration profile of thin blended poly(vinyl methyl ether)/polystyrene films N2 - The composition of thin films of polymer blends in vertical direction is still under discussion. For explaining the thickness dependence of some properties like the thermal glass transition temperature, a three-layer model has been introduced consisting of an adsorbed layer with a reduced segmental mobility at the substrate, a bulk-like layer in the middle of the film and an outermost surface layer with a higher molecular mobility. X-ray photoelectron spectroscopy (ER-XPS) measurements with a varying excitation energy from 400 eV to 1486.6 eV and, herewith, an information depth from 1.5 nm to 10 nm were performed at PVME/PS films with compositions of 25/75 wt% and 50/50 wt% and thicknesses between 15 nm and 190 nm. As expected, it was found that the PVME concentration decreases with increasing information depth. Secondly, a complex correlation between the PVME concentration at the surface and the film thickness was found. The PVME concentration increases with decreasing film thickness until a maximum at 30 nm. For thinner films, the PVME concentration decreases. These data agree with previous investigations obtained with specific heat spectroscopy. We thank BESSY II (HZB) for the allocation of beamtime at the HE-SGM beamline and for technical support. DFG (Project number 124846229) is acknowledged for financial support. T2 - German Conference for Research with Synchrotron Radiation, Neutrons and Ion Beams at Large Facilities (SNI2022) CY - Berlin, Germany DA - 05.09.2022 KW - X-ray photoelectron spectroscopy KW - Miscible polymer films KW - Depth profiling PY - 2022 AN - OPUS4-55654 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolmangadi, Mohamed Aejaz A1 - Szymoniak, Paulina A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Molecular dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase separation N2 - For the first time, dielectric and calorimetric investigations of a homologous series of Janus polynorbornenes with rigid main backbones and flexible −Si(OR)3 side groups of differing length alkyl chains (R = propyl, butyl, hexyl, octyl, and decyl) is reported. Generally, this class of polymers has some potential for applications in the field of gas separation membranes. Two dielectrically active processes are observed at low temperatures, denoted as β- and α-relaxation. The former can be assigned to localized fluctuations, while the latter is related to the glassy dynamics of the flexible −Si(OR)3 side groups, creating a nanophase separation in both the alkyl chain-rich and backbone-rich domains. This is confirmed through temperature-modulated differential scanning calorimetry (TMDSC) measurements and X-ray scattering experiments. The glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC, are determined for the first time using fast scanning calorimetry employing both fast heating and cooling rates. This is complemented with scattering experiments that show how the size of the alkyl chain-rich domains increases with the side chain length. Alongside these results, a significant conductivity contribution was observed for all poly(tricyclononenes) with −Si(OR)3 side groups, which is interpreted in terms of a percolation model. T2 - DPG Online Spring Conference 2021 CY - Online meeting DA - 22.03.2021 KW - Dynamics KW - Glass transition KW - Conductivity PY - 2021 AN - OPUS4-52335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fortini, Renata A1 - Meyer-Plath, A. A1 - Kehren, D. A1 - Gernert, U. A1 - Agudo Jácome, Leonardo A1 - Sturm, Heinz T1 - Measurement of flexural rigidity of multi-walled carbon nanotubes by Dynamic Scanning Electron Microscopy N2 - In this work the flexural rigidity of individual large diameter multi-walled carbon nanotubes (MWCNTs) was investigated. The bending modulus were obtained by detecting the resonance frequencies of mechanically excited cantilevered carbon nanotubes using the so-called dynamic scanning electron microscopy technique, and applying the Euler–Bernoulli beam theory. For the nanotubes studied, we determined a modulus of up to 160 GPa. This agrees with values reported by other authors for MWCNTs produced by catalytic chemical vapor deposition, however, it is 6-8 times smaller than values reported for single and multi-walled carbon nanotubes produced by arc-discharge synthesis. Toxicological studies with carbon nanotubes have been showing that inhaled airborne nanofibers that reach the deep airways of the respiratory system may lead to serious, asbestos-like lung diseases. These studies suggested that their toxicity critically depends on the fiber flexural rigidity, with high rigidity causing cell lesions. To complement the correlation between observed toxicological effects and fiber rigidities, reliable and routinely applicable measurement techniques for the flexural rigidity of nanofibers are required. KW - Flexural rigidity KW - Bending modulus KW - Resonance frequency KW - Carbon nanotubes KW - Fiber toxicology PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514190 DO - https://doi.org/10.3390/fib8050031 SN - 2079-6439 VL - 8 IS - 5 SP - 31 PB - MDPI AN - OPUS4-51419 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Ciornii, Dmitri A1 - Hodoroaba, Vasile-Dan A1 - Benismail, Nizar A1 - Altmann, Korinna T1 - Project 2: Interlaboratory Comparison on detection and quantitative assessment of microplastics by use of spectroscopic and thermo-analytical methods N2 - Validated and standardized methods in microplastic analysis are indispensable for robust monitoring and regulation. Alongside also reference materials are urgently needed. An interlaboratory comparison (ILC) offers a powerful tool to address both these challenges. The present study aimed to compare the precision and accuracy of various methods for the detection and quantification of microplastic in a water-soluble matrix. Additionally, it evaluated the suitability of the test materials (containing environmentally relevant plastic polymers) to serve as reference materials for the microplastic analysis. In this ILC several most used thermo-analytical and spectroscopic methods have been addressed: Pyrolysis-Gas Chromatography Mass Spectrometry (Py-GC/MS), Thermal Extraction-Desorption Gas Chromatography Mass Spectrometry (TED-GC/MS), micro-Fourier Transform Infrared Spectroscopy (µ-FTIR), and micro-Raman Spectroscopy and Laser Direct Infrared Spectroscopy (LDIR). Microplastic powders of polyethylene (PE) and polyethylene terephthalate (PET) were used to assess suitability of the test materials (microplastic tablets) for method validation and use in the ILCs. The participants were guided with a SOP how to dissolve the test samples and, depending on their selected method, either quantify the number of particles (by the spectroscopic methods) or determine the mass fraction of microplastic particles per sample (by the thermo-analytical methods). KW - ILC KW - Microplastic KW - FTIR KW - Raman KW - TED-GC/MS KW - Py-GC/MS PY - 2024 SP - 1 EP - 16 AN - OPUS4-60612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard T1 - DACHS/MOFs/AutoMOFs_2/Synthesis N2 - The DACHS (Database for Automation, Characterization and Holistic Synthesis) project aims to create completely traceable experimental data, covering syntheses, measurements, analyses, and interpretations. DACHS_MOFs focuses on the synthesis and characterisation of metal-organic frameworks, across multiple, automation-assisted experimental series (AutoMOFs), with the overall goal of producing reproducible MOF samples through tracking of the synthesis parameters. DACHS_MOFs is simultaneously used to test the DACHS principles. This upload contain synthesis data from AutoMOFs_2 in HDF5 format (.h5). Each .h5 file contains detailed information on the chemical, experimenal, and synthesis parameters used during the synthesis of a single AutoMOF sample. KW - Automation KW - Procedure KW - Synthesis KW - Traceability PY - 2024 DO - https://doi.org/10.5281/zenodo.11236074 PB - Zenodo CY - Geneva AN - OPUS4-60611 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. A1 - Weidner, Steffen T1 - Low Molar Mass Cyclic Poly(L-lactide)s: Separate Transesterification Reactions of Cycles and Linear Chains in the Solid State N2 - L-Lactide (LA) was polymerized with neat tin(II) 2-ethylhexanoate (SnOct2) in toluene at 115 °C at low concentration with variation of the LA/Cat ratio. Cyclic polylactides (cPLAs) with number average molecular weights (Mn) between 7 000 and 17 000 were obtained. MALDI-TOF mass spectrometry also revealed the formation of a few percent of linear chains. Crystalline cPLAs with Mn around 9 000 and 14 000 were annealed at 140 °C in the presence of ScOct2 or dibutyl-2-stanna-1,3-dithiolane (DSTL). Simultaneously, crystallites of extended linear chains and crystallites of extended cycles were formed regardless of the catalyst, indicating that transesterification reaction proceeded different for linear chains and for cycles, governed by thermodynamic control. The formation of extended chain crystallites with low dispersity indicates the existence of symproportionation of short and long chains. A complementary experiment was carried out with a PLA ethyl ester composed mainly of linear chains with a small fraction of cycles KW - Polylactide KW - MALDI-TOF MS KW - Annealing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606228 DO - https://doi.org/10.1039/D4SM00567H SN - 1744-6848 SP - 1 EP - 12 PB - Royal Society of Chemistry (RSC) AN - OPUS4-60622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolmangadi, Mohamed Aejaz A1 - Szymoniak, Paulina A1 - Smales, Glen Jacob A1 - Bermeshev, M. A1 - Schönhals, Andreas A1 - Böhning, Martin T1 - Molecular mobility of polynorbornenes with trimethylsiloxysilyl side groups: Influence of the polymerization mechanism N2 - We report dielectric and calorimetric studies on metathesis and addition-type polytricyclononenes, both based on the same monomer bearing three pendant OSiMe3 groups. For the addition-type polymer, dielectric spectroscopy reveals a β*-process related to the microporosity, whereas for its metathesis counterpart, the segmental dynamics manifests as an α-process related to a glass transition. Besides active dielectric processes, a significant conductivity contribution is detected for both samples which for the microporous additiontype polymer is three orders of magnitude greater than for the metathesis polymer. The broadband dielectric spectroscopy is complemented by detailed calorimetric investigations, comprising DSC, FSC, and TMDSC. The calorimetric methods detected the glass transition for the metathesis polymer in agreement with the observed dielectric α-process. Furthermore, the already reported gas transport properties for both polymers are compared, setting them in correlation with the observed molecular mobility and conductivity behavior. The discussed results reflect significant differences in molecular mobility of the two polymers affecting the appearance of microporosity which strongly determines the gas transport properties. KW - Microporous polymers KW - Molecular mobility KW - Electrical conductivity KW - Membrane polymers KW - Gas separation PY - 2022 DO - https://doi.org/10.22079/JMSR.2021.538060.1495 SN - 2476-5406 VL - 8 IS - 3 SP - 1 EP - 9 PB - Membrane Processes Research Laboratory (MPRL) CY - Tehran AN - OPUS4-54303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waniek, Tassilo A1 - Ghasem Zadeh Khorasani, Media A1 - Braun, Ulrike A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Water as side effect of reinforcing boehmite filler Local changes in anhydride cured epoxy resin N2 - Nanocomposites offer wide opportunities for lightweight constructions and enable reduction of weight and volume. Beside macroscopic toughening nanoparticle reinforced polymers show a soft interface around boehmite (AlOOH) filler nanoparticles. A related strong interaction between boehmite and the anhydride cured resin system is widely suspected in literature but not determined by structural Analysis. Determination of the molecular structure is important to allow simulations approaching the real system and predict future reinforcing effects. DRIFT (diffuse refletance infrared fourier transformed) spectra of the boehmite reinforced anhydride cured epoxy show significant changes in the molecular structure compared to the neat polymer. Further investigations of the interactions between the single components of the resin system and the boehmite filler pointed out reactions between released water released from the boehmite filler and the anhydride hardener or amine accelerator. This leads to the discussion of competing polymerisation mechanisms that highly influence the polymer properties. Ongoing experiments and literature research approve that this impact of water is able to locally change the stoichiometrie, alter the curing mechanism or support an inhomogeneous crosslink density. T2 - Polydays 2019 CY - Erwin-Schrödinger-Zentrum, Berlin Adlershof, Germany DA - 11.09.2019 KW - Nanocomposites KW - Epoxy KW - FTIR spectroscopy KW - Boehmite alumina PY - 2019 AN - OPUS4-49010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolmangadi, Mohamed Aejaz A1 - Szymoniak, Paulina A1 - Smales, Glen Jacob A1 - Alentiev, D. A1 - Bermeshev, M. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Molecular Dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase Separation N2 - For the first time, dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbones and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl) is reported. Generally, this class of polymers has some potential for applications in the field of gas separation membranes. Two dielectrically active processes are observed at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter is related to the glassy dynamics of the flexible -Si(OR)3 side groups, creating a nanophase separation in both the alkyl chain rich and backbone rich domains. This is confirmed through temperature modulated DSC measurements and X-ray scattering experiments. The glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC, are determined for the first time using Fast Scanning Calorimetry employing both fast heating and cooling rates. This is complimented with scattering experiments that show how the size of the alkyl chain rich domains increases with chain length. Alongside these results, a significant conductivity contribution was observed for all poly(tricyclononenes) with -Si(OR)3 side groups, which is interpreted in terms of a percolation model. KW - Polynorbornenes KW - Broadband Dielectric Spectrscopy KW - Advanced calorimetry PY - 2020 DO - https://doi.org/10.1021/acs.macromol.0c01450 VL - 53 IS - 17 SP - 7410 EP - 7419 PB - ACS AN - OPUS4-51196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -