TY - CONF A1 - Dudziak, Mateusz A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Thermal properties of polymer nanocomposites based on polycarbonate (PC) and boehmite N2 - Nanocomposites are extremely versatile due to their physicochemical properties, which differ significantly from bulk homopolymers. One of the inorganic nanomaterials which are increasingly used as a filler in polymer matrices is boehmite, typically used as an inexpensive flame retardant. Here, it is used as a nanofiller in polycarbonate and polyamide, expecting to improve their mechanical properties. For industrial use boehmite is obtained by the solvothermal method, resulting in a layered nanomaterial, whereas naturally it occurs as single crystals with the size of <100µm. In this work we are obtaining and isolating boehmite crystals by a bottom-up method, in which a reaction between aluminum nitride and sodium hydroxide. Obtaining boehmite as microcrystals is necessary for its analysis and characterization, as well as to investigate its interaction with polymer matrices at the polymer/particle interface. Here, the obtained particles in polymer matrices are characterized with differential scanning calorimetry and thermogravimetry analysis. T2 - 6th International Conference on Multifunctional, Hybrid and Nanomaterials CY - Sitges, Spain DA - 11.03.2019 KW - Boehmite KW - Polycarbonate PY - 2019 AN - OPUS4-47769 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dudziak, Mateusz A1 - Silbernagl, Dorothee A1 - Sturm, Heinz T1 - Thermal properties of polymer nanocomposites based on polycarbonate (PC) and boehmite N2 - Nanocomposites are extremely versatile due to their physicochemical properties, which differ significantly from bulk homopolymers. One of the inorganic nanomaterials which are increasingly used as a filler in polymer matrices is boehmite, typically used as an inexpensive flame retardant. Here, it is used as a nanofiller in polycarbonate and polyamide, expecting to improve their mechanical properties. For industrial use boehmite is obtained by the solvothermal method, resulting in a layered nanomaterial, whereas naturally it occurs as single crystals with the size of <100µm. In this work we are obtaining and isolating boehmite crystals by a bottom-up method, in which a reaction between aluminum nitride and sodium hydroxide. Obtaining boehmite as microcrystals is necessary for its analysis and characterization, as well as to investigate its interaction with polymer matrices at the polymer/particle interface. Here, the obtained particles in polymer matrices are characterized with differential scanning calorimetry and thermogravimetry analysis. T2 - DPG-Frühjahrstagung 2019 CY - Regensburg, Germany DA - 31.03.2019 KW - Boehmite KW - Polycarbonate PY - 2019 AN - OPUS4-47768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Data processing and nonlinear curve Fitting with fityk N2 - A brief introduction into fityk is given. The introduction is followed by a pratical session. Fityk is a versatile data processing tool for nonlinear curve fitting. T2 - AFM Data analysis seminar CY - Online meeting DA - 23.02.2021 KW - Fityk KW - Curve fitting KW - Analysis KW - Raman KW - IR KW - XPS PY - 2021 AN - OPUS4-52154 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zutta Villate, J. M. A1 - Hahn, Marc Benjamin T1 - Radioactive gold nanoparticles for cancer treatment N2 - Dose enhancement by gold nanoparticles (AuNP) was shown to increase the biological effectiveness of radiation damage in biomolecules and tissue. Most of the current studies focus on external beam therapy on combination with AuNP. Here we present a Monte-Carlo study (Geant4) to characterise radioactive AuNP. Radioactive 198 Au emits beta and gamma rays and is considered for applications with solid tumours. To effectively apply 198 AuNP their energy deposit characteristics have to be determined in terms of intrinsic and extrinsic properties e.g. AuNP diameter, AuNP density, and their clustering behaviour. After each decay process, the energy deposit, inelastic scattering events, kinetic energy spectrum of secondary particles within the AuNP themselves and in a spherical target volume of water up to 1 μm radius were determined. Simulations were performed for AuNP radii ranging from 2.5 nm to 20 nm radius, different cluster sizes and densities. The results show an increase of the energy deposit in the vicinity of the AuNP up to 150 nm. This effect nearly vanishes for distances up to one micron. For the case of AuNP clusters and the same activity, the enhancement of the energy deposit increases with the relative gold mass percentage and therefore can be adjusted by changing AuNP radius or clustering behaviour. KW - Gold KW - Nanoparticle KW - Cancer KW - Monte-Carlo KW - Simulation KW - Cluster PY - 2019 DO - https://doi.org/10.1140/epjd/e2019-90707-x SN - 1434-6060 SN - 1434-6079 VL - 73 IS - 95 SP - 1 EP - 7 PB - Springer CY - Berlin AN - OPUS4-47964 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin T1 - Temperature in micromagnetism: Cell size and scaling effects of the stochastic Landau-Lifshitz equation N2 - The movement of the macroscopic magnetic moment in ferromagnetic systems can be described by the Landau-Lifshitz (LL) or Landau-Lifshitz-Gilbert (LLG) equation. These equations are strictly valid only at absolute zero temperature. To include temperature effects a stochastic version of the LL or LLG equation for a spin density of one per unit cell can be used instead. To apply the stochastic LL to micromagnetic simulations, where the spin density per unit cell is generally higher, a conversion regarding simulation cell size and temperature has to be established. Based on energetic considerations, a conversion for ferromagnetic bulk and thin film systems is proposed. The conversion is tested in micromagnetic simulations which are performed with the Object Oriented Micromagnetic Framework (OOMMF). The Curie temperatures of bulk Nickel, Cobalt and Iron systems as well as Nickel thin-film systems with thicknesses between 6.3 mono layer (ML) and 31ML are determined from micromagnetic simulations. The results show a good agreement with experimentally determined Curie temperatures of bulk and thin film systems when temperature scaling is performed according to the presented model. T2 - EUROMAT 2019 CY - Stockholm, Sweden DA - 01.09.2019 KW - Magnetic nanoparticles KW - Stochastic Landau Lifshitz Gilbert equation KW - Magnetic moment KW - Landau Lifshitz equation KW - Exchange interaction KW - OOMMF KW - Object oriented micromagnetic framework KW - Temeprature scaling KW - LLG KW - Ferromagnetism KW - Micromagnetism PY - 2019 AN - OPUS4-48762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Marc Benjamin A1 - Zutta Villate, J. M. T1 - Radioactive gold nanoparticles for cancer treatment: Size and cluster dependent damage studied by Geant4 Monte-Carlo simulations N2 - Dose enhancement by gold nanoparticles (AuNP) was shown to increase the biological effectiveness of radiation damage in biomolecules and tissue. Most of the current studies focus on external beam therapy on combination with AuNP. Here we present a Monte-Carlo study (Geant4) to characterise radioactive AuNP. Radioactive ¹⁹⁸Au emits beta and gamma rays and is considered for applications with solid tumours. To effectively apply ¹⁹⁸AuNP their energy deposit characteristics have to be determined in terms of intrinsic and extrinsic properties e.g. AuNP diameter, AuNP density, and their clustering behaviour. After each decay process, the energy deposit, inelastic scattering events, kinetic energy spectrum of secondary particles within the AuNP themselves and in a spherical target volume of water up to 1 μm radius were determined. Simulations were performed for AuNP radii ranging from 2.5 nm to 20 nm radius, different cluster sizes and densities. The results show an increase of the energy deposit in the vicinity of the AuNP up to 150 nm. This effect nearly vanishes for distances up to one micron. For the case of AuNP clusters and the same activity, the enhancement of the energy deposit increases with the relative gold mass percentage and therefore can be adjusted by changing AuNP radius or clustering behaviour. T2 - EUROMAT 2019 CY - Stockholm, Sweden DA - 01.09.2019 KW - DNA KW - Dosimetry KW - Microdosimetry KW - Geant4 KW - MCS KW - Nanoparticle KW - AuNP KW - Gold Nanoparticle KW - low energy electrons KW - LEE KW - OH radicals KW - particle scattering KW - Radiationtherapy KW - Radioactive decay KW - Monte-Carlo simulation KW - Energy deposit KW - DNA damage PY - 2019 AN - OPUS4-48763 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 - CONF A1 - Pauw, Brian Richard A1 - Topolniak, Ievgeniia A1 - Schenderlein, Matthias A1 - Sturm, Heinz T1 - Nano polymer (composite) printing N2 - This talk introduces the PolyPoly, a new device at BAM which enables the three-dimensional structuring of polymer nanocomposites with an extremely high resolution of 150x150x600 nm. Initial examples and findings will be shown. T2 - BAM-IFW Workshop CY - Dresden, Germany DA - 28.03.2019 KW - Multiphoton laser structuring KW - Polymer nanocomposites KW - 3d structuring KW - Additive manufacturing PY - 2019 AN - OPUS4-48041 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Szymoniak, Paulina A1 - Qu, Xintong A1 - Schönhals, Andreas A1 - Sturm, Heinz ED - Sinapius, M. ED - Ziegmann, G. T1 - Characterization of Polymer Nanocomposites N2 - The complex effect of nanoparticles on an epoxy-based and anhydride cured DGEBA/Boehmite nanocomposite with different particle concentrations is considered in this chapter. A combination of X-ray scattering, calorimetry (fast scanning and temperature modulated calorimetry) and dielectric spectroscopy was employed to characterize the structure, vitrification kinetics and the molecular dynamics of the nanocomposites. Firstly, the unfilled polymer was found to be intrinsically heterogeneous, showing regions with different crosslinking density, indicated by two separate dynamic glass transitions. Moreover, the glass transition temperature decreases with increasing nanoparticle concentration, as a result of changes in the crosslinking density. In addition, it was shown that the incorporation of nanoparticles can result in simultaneous increase in the number of mobile segments for low nanoparticle concentrations and on the other hand, for higher loading degrees the number of mobile segments decreases, due to the formation of an immobilized interphase. KW - Rigid amorphous fraction KW - Epoxy nanocomposites KW - X-ray scattering KW - Differential scanning calorimetry KW - Broadband dielectric spectroscopy KW - Flash DSC PY - 2021 DO - https://doi.org/10.1007/978-3-030-68523-2_4 SP - 55 EP - 77 PB - Springer Nature AN - OPUS4-52698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sachse, René A1 - Pflüger, Mika A1 - Velasco-Vélez, Juan-Jesús A1 - Sahre, Mario A1 - Radnik, Jörg A1 - Bernicke, Michael A1 - Bernsmeier, Denis A1 - Hodoroaba, Vasile-Dan A1 - Krumrey, Michael A1 - Strasser, Peter A1 - Hertwig, Andreas A1 - Kraehnert, Ralph T1 - Operando electrochemical spectroscopic ellipsometry: Material properties of highly active mesoporous IrO IrOxfilms revealed under realistic OER conditions N2 - Rising energy demand and the impending climate change require the development of a sustainable, fossil-free fuel and chemical production on a global scale. Hydrogen production via water electrolysis will be a fundamental cornerstone in this endeavor. The activity and stability of respective electrode coatings strongly depends on the coating's properties, i.e. phase composition, crystallinity, electrical conductivity, accessible surface, wettability and many other factors. The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physicochemical properties. However, those relations can be complex, and are strongly influenced also by the reaction environment. Hence, operando analysis of the catalyst material during catalysis at realistic potentials and current densities is highly desirable. Yet, many analytical techniques cannot be applied in liquid environments at realistic potentials and current densities. We propose environmental ellipsometric analysis in a dedicated electrochemical flow cell as a new method to evaluate gas evolution reactions operando under realistic working conditions. Figure 1 illustrates schematically the developed technique. Key factors to success are highly active model-type catalysts with template-controlled porosity, a suitable sample environment, a deep understanding of the spectroscopic method and respective model development, as well as concise cross validation with numerous other analytical techniques. The method was developed and validated by analyzing a calcination series (300 - 600°C) of mesoporous templated IrOx films ex-situ and operando under oxygen evolution reaction (OER) conditions. The employed environmental electrochemical spectroscopic ellipsometric analysis (ECSE) revealed during OER the change of optical and electronic properties, i.e. the dielectric functions (real ε1 and imaginary part ε2), electrical and electronic properties such as resistivity (ρ) and band-to-band transitions (p-d band transitions). Film thickness and porosity were validated by means of scanning electron microscopy (SEM), X-ray reflectometry (XRR) or ellipsometric porosimetry (EP), electrical and electronic properties by means of conductivity measurements, X-ray photoelectron spectroscopy (XPS) or UV-Vis-NIR absorption spectroscopy. The electronic structures of the catalysts from valence electron energy loss spectra (VEELS) derived from the real (ε1) and imaginary part (ε2) of the dielectric function from SE measurements reveal a direct correlation with electrochemical activities in OER. In the presentation reversible and irreversible potential-dependent changes of the catalyst properties during operation will be discussed along with the dynamics of gas formation, transport and dissolution T2 - E MRS 2021 SPRING MEETING CY - Online meeting DA - 31.05.2021 KW - Spectroscopic ellipsometry KW - Ectrocatalysis KW - Oxygen evolution reaction KW - Mesoporous iridium oxide films KW - Non-destructive operando analysis PY - 2021 AN - OPUS4-52929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -