TY - JOUR A1 - Fahmy, Alaa A1 - Adham-Zomrawy, A. A1 - Saeed, A. M. A1 - El-Arab, M. A. E. A1 - Shehata, H. A1 - Friedrich, J. T1 - Degradation of organic dye using plasma discharge: optimization, pH and energy N2 - Decolorization of Acid Orange 142 (AO142) as important water pollutant was observed on the exposure of the dye solutions to an atmospheric non-thermal gas plasma. Aresponse Surface methodology (RSM) combined with a central composite design (CCD) was utilized to optimize the main factors (variables) affecting the degradation efficiency (response) of AO142, such as the applied voltage, the gap distance between the high voltage electrode and the surface of the solution. The regression analysis showed that a first-order polynomial model well fits the experimental data with a coefficient of determination R2=0.96. FT-IR, UV-vis,TOCand GC-MS measurements were used to investigate the decolorization of the dye on exposure to the plasma discharges. A possible Degradation pathway was postulated. Additionally, the conductivity and pH changes during the treatment were also evaluated. The plasma treatment combined with Fe2+ (plasma Fenton reaction) exhibited a higher degradation efficiency, higher energy yield connected with lower energy consumption in comparison to the plasma treatment without Fe2+ addition. KW - Advanced Oxidation PY - 2020 DO - https://doi.org/10.1088/2516-1067/ab6703 VL - 2 IS - 1 SP - 015009 PB - IOP publishing Ltd AN - OPUS4-50467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Walther, M. A1 - Jung, C. M. A1 - Bergmann, R. A1 - Pietzsch, J. A1 - Rode, K. A1 - Fahmy, K. A1 - Mirtschink, P. A1 - Stehr, S. A1 - Heintz, A. A1 - Wunderlich, G. A1 - Kraus, Werner A1 - Pietzsch, H.-J. A1 - Kropp, J. A1 - Deussen, A. A1 - Spies, H. T1 - Synthesis and Biological Evaluation of a New Type of 99mTechnetium-Labeled Fatty Acid for Myocardial Metabolism Imaging PY - 2007 SN - 1043-1802 SN - 1520-4812 VL - 18 SP - 216 EP - 230 CY - Washington, DC AN - OPUS4-14514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, Alaa A1 - Saied, M. A. A. A1 - Morgan, N. A1 - Abdelbary, H. A1 - Bahy, S. M. A1 - Schönhals, Andreas A1 - Friedrich, J. F. T1 - Modified polyvinyl chloride membrane grafted with an ultra-thin polystyrene film: structure and electrochemical properties N2 - The work explores the synthesis and the properties of a novel composite membrane System based on modified polystyrene (PS) grafted onto a polyvinyl chloride (PVC) membrane. PVC membranes were prepared by solution-casting followed by exposure to an atmospheric pressure dielectric barrier discharge (DBD) with O2 to obtain an activated Surface for grafting PS to it. Moreover, the thus prepared membranes were chemically modified furthermore by amination with polyethyleneimine or sulfonation with 4 M sulfuric acid. The membrane surface characteristics such as wettability, structure and morphology were investigated using water contact angle measurements, attenuated total reflection Fourier transform infrared spectroscopy and scanning electron microscopy experiments. The thermogravimetric stability and electrolytic responses of the membranes were studied utilizing TGA, ion exchange capacity (IEC), and solvent uptake. A significant result of plasma and chemical modification was to produce a membrane material with low permeability. Thus, the methanol permeability of the sulfonated membranes measured for 12 h was measured to 2.34$10� 8 cm2 s� 1 compared to 177.00$10� 8 cm2 s� 1 of Nafion 117®which is considered as a benchmark. This result indicates that the prepared sulfonated samples are an innovative and effective material for decreasing the methanol crossover in fuel cells to a great extent. This makes the PVC-g-St membranes are promising and attractive as new materials for polyelectrolyte membrane for fuel cells. KW - Electrolyte membrane KW - Fuell cells PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526794 DO - https://doi.org/10.1016/j.jmrt.2021.04.018 VL - 12 SP - 2273 EP - 2284 PB - Elsevier B.V. AN - OPUS4-52679 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zosef, M. A1 - Fahmy, Alaa A1 - El Hotaby, W. A1 - Hassan, A. A1 - Khalil, A. A1 - Anis, B. T1 - High performance graphene-based PVF foam for lead removal from water N2 - The synthesis and optimization of superior and eco-friendly sorbents for Pb(II) pose a great challenge in the field of water treatment. The sorbent was developed by introducing graphene oxide (GO) into the matrix of polyvinyl formaldehyde (PVF) foam. The immobilization of GO in PVF results in significant increase in the maximum adsorption capacity (Qt) of GO powder for Pb(II), from ≈800 to ≈1730 mg g−1 in the case of GO/PVF foam. As compared with GO powder in Pb(II) aqueous solutions, PVF matrix keeps GO sheets stable without any agglomeration. The large surface area of GO sheet allows the abundant oxygenated functional groups on its surface to participate effectively in the Pb(II) adsorption process, leading to the huge increase of the Qt. Adsorption isotherms and kinetic studies indicated that the sorption process of Pb(II) on GO/PVF was done on heterogenous surface by ion-exchange reaction. The GO/PVF foam showed an excellent reusability for more than 10 cycles with almost the same efficiency and without any significant change in its physical properties. KW - Water treatment KW - Graphene oxide KW - Lead ions KW - Polyvinyl formaldehyde foam KW - Superior sorbent PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523013 DO - https://doi.org/10.1016/j.jmrt.2020.08.011 VL - 9 IS - 5 SP - 11861 EP - 11875 PB - Elsevier B.V. AN - OPUS4-52301 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Saeed, A. A1 - Dawood, U. A1 - Abdelbary, H. A1 - Altmann, Korinna A1 - Schönhals, Andreas T1 - Nano-MnO2/xanthan gum composite films for NO2 gas sensing N2 - Nowadays, sensors based on polymers/nanostructured metal oxide composites have been investigated exten-sively because of their sensitivity to NO2 gas at ambient temperature. In this work, nanocomposite membranes of xanthan gum (XG) with different contents of MnO2 nanoparticles were prepared as a potential NO2 gas sensor operating at room temperature by a simple one-step oxidation-reduction reaction. The structural, morphological, thermal, and electrical properties of the composite membrane were investigated. The FT-IR results confirm the successful preparation of MnO2 through the oxidation of XG by KMnO4 and reveal further the structural changes of the XG/MnO2 nanocomposite upon its exposure to NO2 gas. The capping of the synthesized MnO2 nano-particles by XG, the surface composition of the XG/MnO2 nanocomposite membranes, and the effect of NO2 gas on the surface composition was investigated using the XPS technique. The DC conductivity and dielectric loss of nanocomposites were higher than for neat XG. The conductivities of the nanocomposites XG/MO-4, XG/MO-4/ low NO2, and XG/MO-4/high NO2 composites are half, one, and three orders of magnitude higher than that for pure XG revealing a transition from insulating to conductive properties. The results demonstrated that XG/MnO2 nanocomposite membranes are promising for potential applications in NO2 gas sensing. KW - Gas sensors KW - Membranes KW - Metal oxides KW - Nanocomposites KW - Semiconductors PY - 2022 DO - https://doi.org/10.1016/j.matchemphys.2022.127277 SN - 0254-0584 VL - 296 SP - 1 EP - 14 PB - Elsevier B.V. AN - OPUS4-56769 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Mohamed, T.A. A1 - Schönhals, Andreas T1 - Structure of plasma poly(acrylic acid): Influence of pressure and dielectric properties N2 - Thin poly(acrylic acid) PAA films were deposited by pulsed plasma polymerization on different organic and inorganic substrates. The structure–property relationships of the deposited acrylic acid polymers were studied in dependence on the monomer pressure by various techniques and probes. The surface and bulk properties of the plasma deposited films were investigated by X-ray photoelectron spectroscopy, attenuated total reflection infrared, and broad band dielectric spectroscopy. The experimental infrared frequencies of PAA films are compared with those predicted from quantum mechanical calculation. The concentration of the COOH groups in the film (stored in ambient air) decreased by about 15 % compared to the as-prepared sample. The plasma deposited PAA probably form a highly branched product. However, the dielectric measurements show that in addition to the hydrogen bonds, self condensation process was able to hinder the localized fluctuation as well. These processes lead to form a cross-linked network polymer film. Nevertheless, a low energy is sufficient to break these processes during heating at atmospheric pressure. Therefore, homogenized samples with free branches (functional group) were obtained after a first heating with structures close to conventional polymerized acrylic acid. Thus, a thermally stable product was obtained. KW - Acrylic acid KW - Plasma polymerization KW - Dielectric properties KW - Thermal stability KW - Aging KW - Monomer pressure PY - 2015 DO - https://doi.org/10.1007/s11090-014-9603-8 SN - 0272-4324 VL - 35 IS - 2 SP - 303 EP - 320 PB - Plenum Publ. Corp. CY - New York, NY, USA AN - OPUS4-32711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Mix, Renate A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Structure of plasma-deposited copolymer films prepared from acrylic acid and styrene: Part I dependence on the duty cycle N2 - Copolymers of acrylic acid and styrene (AA/S) were prepared by pulsed plasma deposition and their structures were studied in dependence on the duty cycle (DC) for a fixed composition of 1:1. As a result, low values of DC doses preserve the structure of monomers in the plasma deposited polymers while high DC leads to a higher degree of fragmentation and a loss in regular structure. Regarding plasma copolymerisation as a feasible method to finish surfaces with a definite number of functional groups it is necessary to characterize both, the chemical nature and the physical properties of the deposited layer. Therefore, a combination of different methods was employed for the characterization of thin plasma copolymer films (FTIR, dielectric spectroscopy, differential scanning calorimetry, X-ray photoelectron spectroscopy (XPS)). Special attention was paid on the unambiguous identification of COOH groups at the surface after derivatization with trifluoroethanol by XPS and in the volume by FTIR. The glass transition temperature of the copolymer system is lower than that for the both plasma deposited homopolymers and increases with the DC in difference to plasma deposited poly(acrylic acid). The dielectric measurements showed that the plasma deposited films were not thermally stable and underwent an undesired post-plasma chemical reaction. The results obtained by dielectric spectroscopy are discussed in detail in comparison with the data from FTIR and XPS measurements. KW - Plasmapolymerisation KW - Copolymerisation KW - Acrylic acid–styrene copolymer KW - Dynamic mobility KW - Plasma copolymerisation KW - Surface functionalization KW - Thin film properties PY - 2012 DO - https://doi.org/10.1002/ppap.201100117 SN - 1612-8850 SN - 1612-8869 VL - 9 IS - 3 SP - 273 EP - 284 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-25654 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Friedrich, Jörg Florian T1 - Degradation behavior of thin polystyrene films on exposure to Ar plasma and its emitted radiation N2 - Spin-coated films of amorphous polystyrene (PS) were exposed to argon plasma for a few seconds to several minutes. The PS film was either in direct contact with the plasma or was shielded from the direct plasma contact by filters with different cutoff wavelengths in the vacuum UV region or by a Faraday cage (FC) made from metal mesh to prevent the impinging of charged species. Only energy-rich neutrals and plasma radiation may be operative in presence of the FC. lithium fluoride (LiF) filter protects the sample from direct contact with the plasma. Wavelengths of plasma radiation shorter than c. 105 nm (≈ 11.8 eV) were cut off. Glass filters made of fused SiO2 have a cutoff at λ ≈175?nm completely the vacuum UV radiation of plasma (ca. 175 nm ≈ 7.0 eV). These energies are sufficient to produce C–C, C–H bond scissions in case of direct Ar plasma exposure and Ar plasma exposure with use of the LiF filter. Only quartz glass shielding did not produce significant effects on the polymer surface in comparison to the reference PS, either in surface energy or O/C ratio or in IR spectra. Oxygen plasma has worked most aggressive and had etched the PS film, thus establishing a steady state between introduction of new oxygen functionalities and polymer etching. Ar plasma exposure produces also oxidation and etching of the polymer films as the oxygen plasma. Using of a FC during Ar plasma exposure or the LiF filter a slightly weaker oxidation was observed. KW - Polystyrene KW - Plasma treatment KW - Plasma emitted radiation KW - Degradation KW - Thin films PY - 2013 DO - https://doi.org/10.1080/01694243.2012.705528 SN - 0169-4243 SN - 1568-5616 VL - 27 IS - 3 SP - 324 EP - 338 PB - VNU Science Press CY - Utrecht AN - OPUS4-26315 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - BOOK A1 - Fahmy, A. A1 - Friedrich, Jörg Florian T1 - Structure property relationship of plasma polymer films - Plasma polymerization, plasma treatment and characterization methods PY - 2012 SN - 978-3-8443-2096-1 SP - 1 EP - 160 PB - Lambert academic publishing AN - OPUS4-25390 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Mix, Renate A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Surface and bulk structure of thin spin coated and plasma-polymerized polystyrene films N2 - Polystyrene (PS) spin coated thin films were modified by O2 and Ar plasma as well as by UV irradiation treatments. The modified PS samples were compared with plasma polymerized and commercial polystyrene. The effects of plasma (O2 and Ar) and UV irradiation treatments on the surface and the bulk properties of the polymer layers were discussed. The surface properties were evaluated by X-ray Photoelectron Spectroscopy and Contact angle measurements and the bulk properties were investigated by FTIR and dielectric relaxation spectroscopy. As a result only one second treatment time was sufficient to modify the surface. However, this study was also dedicated to understand the effect of plasma and plasma irradiation on the deposited layers of plasma polymers. The dielectric measurements showed that the plasma deposited films were not thermally stable and underwent an undesired post-plasma chemical oxidation. KW - Surface and bulk characterization KW - Plasma polymerization KW - Polystyrene KW - Surface modification KW - Thermal stability KW - Plasma polymers PY - 2012 DO - https://doi.org/10.1007/s11090-012-9372-1 SN - 0272-4324 VL - 32 IS - 4 SP - 767 EP - 780 PB - Plenum Publ. Corp. CY - New York, NY, USA AN - OPUS4-26264 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Mix, Renate A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Structure of plasma-deposited copolymer films prepared from acrylic acid and styrene: Part II variation of the comonomer ratio N2 - Copolymers of acrylic acid and styrene (AA/S) were prepared by pulsed plasma deposition technique. Their structure–property relationships were studied in dependence on the comonomer ratio. Both, the regularity of the structure and the composition of the thin copolymer films were investigated by bulk-sensitive (dielectric spectroscopy, FTIR, and differential scanning calorimetry) as well as surface-sensitive methods such as X-ray photoelectron spectroscopy (XPS). For an unambiguous identification of the functionality of the deposited films the COOH groups were estimated by derivatization with trifluoroethanol and subsequent XPS measurement as well as by the quantitative analysis of the FTIR data. As a result, the concentration of COOH groups on the surface and in the bulk is increasing with the fraction of AA in precursor mixture in a non-monotonous way but similar to the dependence obtained by conventional free radical polymerization. KW - Acrylic acid-styrene copolymer KW - Bulk properties KW - Dielectric properties KW - Plasma polymerization KW - Surface functionalization PY - 2013 DO - https://doi.org/10.1002/ppap.201200110 SN - 1612-8850 SN - 1612-8869 VL - 10 IS - 9 SP - 750 EP - 760 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-29096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Reaction of water with (radicals in) plasma polymerized allyl alcohol (and formation of OH-rich polymer layers) N2 - The pulsed plasma polymerization of allyl alcohol was employed under the aspect of maximal retention of OH groups and the formation of a regular polymer structure. It should be noted that earlier investigations on plasma polymers deposited from allyl alcohol did not show extensive postplasma addition of oxygen and water vapor from ambient air during storage, measuring the elemental O/C ratio by means of X-ray photoelectron spectroscopy (XPS).The identification of OH groups in the plasma polymerized polymer using FTIR spectroscopy was such an indicator for fragmentation. The peak area of OH groups in the film which was stored was increased by about 20% compared to that measured ('in situ'). These phenomenons reflected that moisture and O2 in air played an important role in scavenging the free radicals. The addition of water and more specifically chemical bonding of OH of water in the deposited plasma polymer may serve as an indicator for monomer fragmentation, poly recombination, and the remaining radicals responsible for film formation. Moreover, the dielectric measurements show that the plasma deposited films are not thermally stable but undergo a postplasma chemical reaction during heating, where the reaction kinetics depends on pressure. PY - 2013 DO - https://doi.org/10.1021/jp406186x SN - 1520-6106 SN - 1520-5207 SN - 1089-5647 VL - 117 IS - 36 SP - 10603 EP - 10611 PB - Soc. CY - Washington, DC AN - OPUS4-29105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Oertel, J. A1 - Keller, A. A1 - Prinz, J. A1 - Schreiber, B. A1 - Hübner, R. A1 - Kerbusch, J. A1 - Bald, Ilko A1 - Fahmy, K. T1 - Anisotropic metal growth on phospholipid nanodiscs via lipid bilayer expansion N2 - Self-assembling biomolecules provide attractive templates for the preparation of metallic nanostructures. However, the intuitive transfer of the “outer shape” of the assembled macromolecules to the final metallic particle depends on the intermolecular forces among the biomolecules which compete with interactions between template molecules and the metal during metallization. The shape of the bio-template may thus be more dynamic than generally assumed. Here, we have studied the metallization of phospholipid nanodiscs which are discoidal particles of ~10 nm diameter containing a lipid bilayer ~5 nm thick. Using negatively charged lipids, electrostatic adsorption of amine-coated Au nanoparticles was achieved and followed by electroless gold deposition. Whereas Au nanoparticle adsorption preserves the shape of the bio-template, metallization proceeds via invasion of Au into the hydrophobic core of the nanodisc. Thereby, the lipidic phase induces a lateral growth that increases the diameter but not the original thickness of the template. Infrared spectroscopy reveals lipid expansion and suggests the existence of internal gaps in the metallized nanodiscs, which is confirmed by surface-enhanced Raman scattering from the encapsulated lipids. Interference of metallic growth with non-covalent interactions can thus become itself a shape-determining factor in the metallization of particularly soft and structurally anisotropic biomaterials. KW - Lipid Nanodiscs KW - Metal nanoparticles KW - Infrared spectroscopy KW - Surface-enhanced Raman scattering PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-364303 UR - http://www.nature.com/articles/srep26718 DO - https://doi.org/10.1038/srep26718 SN - 2045-2322 VL - 6 SP - 26718-1 EP - 26718-9 PB - Nature Publishing Group CY - London, UK AN - OPUS4-36430 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Mix, Renate A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Structure of plasma-deposited poly(acrylic acid) films N2 - Poly(acrylic acid) films with a thickness of about 150?nm were deposited using a pulsed plasma onto aluminum and glass. The structure/property relationships of these samples were studied in dependence to the duty cycle (DC) of the plasma by a broad combination of different techniques and probes. For the first time, volume sensitive methods (FTIR, dielectric spectroscopy, and differential scanning calorimetry) are combined with surface analyses i.e. XPS. For an unambiguous identification of COOH groups by XPS, derivatization with trifluoroethanol was accomplished. Quantitative FTIR investigations give qualitatively a dependence of the concentration of COOH groups upon DC similar to that given by XPS investigations. The observed differences are discussed considering the different analytical depths of both methods. The dielectric measurements reveal that the structure of the plasma deposited films is different from that of the bulk material. Moreover, these measurements show also that the plasma deposited films are not thermally stable but undergo a post plasma chemical reaction during heating, where the reaction kinetics depends on DC. PY - 2011 DO - https://doi.org/10.1002/ppap.201000108 SN - 1612-8850 SN - 1612-8869 VL - 8 IS - 2 SP - 147 EP - 159 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-23478 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Mix, Renate A1 - Schönhals, Andreas A1 - Friedrich, Jörg Florian T1 - Structure-property relationship of thin plasma deposited poly(allyl alcohol) films N2 - Poly(allyl alcohol) films with a thickness of about 150 nm were deposited by pulse plasma polymerization onto different substrates (inorganic and organic). The structure/property relationships of these samples were studied in dependence on the duty cycle (DC) of the plasma by a broad combination of different techniques and probes. For the first time volume sensitive methods (FTIR and dielectric spectroscopy) are combined with surface analytics by employing XPS for that system. FTIR spectroscopy gives qualitatively the same dependence of the concentration of the OH groups on DC like XPS. The observed differences are discussed considering the different analytical depths of both the methods. The dielectric measurements show that the plasma deposited films are not thermally stable but undergo a post plasma chemical reaction during heating. The results obtained by dielectric spectroscopy are discussed in detail with the data from FTIR and XPS measurements. KW - Allyl alcohol KW - Dielectric properties KW - Plasma polymerization KW - Surface and bulk characterization KW - Thermal stability PY - 2011 DO - https://doi.org/10.1007/s11090-011-9297-0 SN - 0272-4324 VL - 31 IS - 3 SP - 477 EP - 498 PB - Plenum Publ. Corp. CY - New York, NY, USA AN - OPUS4-23671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, Alaa A1 - Mohamed, T. A. A1 - Abu-Saied, M. A1 - Helaly, H. A1 - El-Desouky, F. T1 - Structure/property relationship of polyvinyl alcohol/ dimethoxydimethylsilane composite membrane: Experimental and theoretical studies N2 - A novel mixed matrix composite has been prepared using solution-casting method at different volume concentrations of polyvinyl alcohol; PVA (50, 67, 75 and 80 %) and fixed amount of Dimethoxydimethylsilane in air atmosphere. The hydrolyzed dimethyldisilanol acts as in-situ cross linker through a wet-out condensation between the hydroxyl moieties of SiOH and PVAOH. Such process improves the mechanical properties of composite membranes as compared to pristine PVA which has been determined as function of varied membrane components to evaluate the structure/property relationships. Furthermore, DFT (B3LYP)/6-31G(d) geometry and frequency computations were carried out for the suggested dimeric PVA structures via 1,3-diol linkage followed by condensation and hydrogen bonding interaction. Vibrational interpretations of composite membranes were proposed based on the computed wavenumbers, Cartesian coordinates displacements for the suggested hydrolyzed products involving the dominant PVA/SiOH/SiOC/SiOSi functional groups compared with those given in literatures. FTIR and EDX provide clear evidences for incorporating silicon to 3D network. Meanwhile, the infrared de-convoluted spectral interpretations ensure 17-30% cross-linked SiOC within the network of Composite membranes. KW - Polyvinyl alcohol KW - Polymer composites PY - 2019 DO - https://doi.org/10.1016/j.saa.2019.117810 SP - 117810 PB - Elsevier AN - OPUS4-49967 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, Alaa A1 - El Sabbagh, M. A1 - Bedair, M. A1 - Gangan, A. A1 - El-Sabbah, M. A1 - El-Bahy, S. A1 - Friedrich, J. T1 - One-step plasma deposited thin SiOxCy films for corrosion resistance of low carbon steel N2 - Tetraethyl orthosilicate (TEOS) was used as a chemical precursor to deposit ultra-thin SiO x C y plasma polymer films onto mild steel surfaces for preventing the corrosion process. The structure–property relationships of the coatings were evaluated by X-ray Photo Spectroscopy (XPS), X-Ray Diffraction (XRD), Fourier Transform InfraRed spectroscopy (ATR-FTIR) and Energy Dispersive X-ray spectroscopy (EDX) completed with Scanning Electron Microscopy (SEM). The SEM micrographs confirmed a pinhole-free surface morphology of the low-pressure deposited plasma polymer films. The TEOS molecules become fragmented in the plasma by numerous collisions with energy-rich electrons and heavier particles. Recombination of fragments and condensation onto the steel substrate is responsible for the formation of organic SiO containing plasma polymer layers. Such thin layers consist of predominantly SiO x structures. Their properties are determined largely by the gap distance between the two samples used as electrodes in the plasma. The efficiency of the corrosion-protecting coating was compared with uncoated samples. The corrosion protection was determined by exposure of samples to 3.5% NaCl aqueous solutions. For this purpose, polarization and Electrochemical Impedance Spectroscopy (EIS) were used to monitor the corrosion. The optimal gap distance between the electrodes was determined for corrosion protection. The best protective efficiency reached more than 97% of the total protection as measured at room temperature. KW - Thin films KW - Corrosion resistance KW - Mild steel KW - Plasma treatments KW - Tetraethyl orthosilicate PY - 2020 DO - https://doi.org/10.1080/01694243.2020.1856539 VL - 35 IS - 16 SP - 1734 EP - 1751 PB - Taylor & Francis AN - OPUS4-52303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Anis, B. A1 - Szymoniak, Paulina A1 - Altmann, Korinna A1 - Schönhals, Andreas T1 - Graphene Oxide/Polyvinyl Alcohol–Formaldehyde Composite Loaded by Pb Ions: Structure and Electrochemical Performance N2 - An immobilization of graphene oxide (GO) into a matrix of polyvinyl formaldehyde (PVF) foam as an eco-friendly, low cost, superior, and easily recovered sorbent of Pb ions from an aqueous solution is described. The relationships between the structure and electrochemical properties of PVF/GO composite with implanted Pb ions are discussed for the first time. The number of alcohol groups decreased by 41% and 63% for PVF/GO and the PVF/GO/Pb composite, respectively, compared to pure PVF. This means that chemical bonds are formed between the Pb ions and the PVF/GO composite based on the OH groups. This bond formation causes an increase in the Tg values attributed to the formation of a strong surface complexation between adjacent layers of PVF/GO composite. The conductivity increases by about 2.8 orders of magnitude compared to the values of the PVF/GO/Pb composite compared to the PVF. This means the presence of Pb ions is the main factor for enhancing the conductivity where the conduction mechanism is changed from ionic for PVF to electronic conduction for PVF/GO and PVF/GO/Pb. KW - Graphene oxide KW - Polyvinyl formaldehyde KW - Lead ions KW - Conductivity PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549588 DO - https://doi.org/10.3390/polym14112303 SN - 2073-4360 VL - 14 IS - 11 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-54958 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fahmy, A. A1 - Al-Nasser, K. S. A1 - Ali, I. O. A1 - Salama, T. M. A1 - Altmann, Korinna A1 - Friedrich, J. F. T1 - Tuning of adhesion of silver nanoparticles onto zeolite ZSM-5 using electrospray ionization (ESI) encapsulation with poly(acrylic acid) deposited by electrospray ionization (ESI) N2 - The electrospray ionization (ESI) method was used for deposition of thin films of poly(acrylic acid) (PAA) onto ZSM-5, Cu/ZSM-5 and Ag-Cu/ZSM-5 zeolites. This method allowed the formation of uniform polymer films of controlled thickness on conductive substrates. The zeolites were prepared home-made. The effect of incorporation of Cu (5 wt.%) and Ag-Cu (1+4 wt.%) onto ZSM-5 on its particle size, unit cell parameters and crystallinity was investigated. The deposited PAA layer acts as a common dispersing agent with its ionic COOH (COO-) groups. The antibacterial activity towards the bacterial strains such as Staphylococcus pneumonia (S. Pneumonia), Bacillus subtilis (B. subtilis), Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) as Gram positive and Gram negative bacteria, respectively, and Aspergillus fumigatus (A. fumigatus), Candida albicans (C. albicans) as Fungi was evaluated. The chemical and physical modifications of ZSM-5, Cu/ZSM-5 and Ag-Cu/ZSM-5 surfaces were characterized by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, atomic force microscopy and X-ray diffraction. The Cu/ZSM-5 and Ag-Cu/ZSM-5 nanocomposites coated with a 10 nm thick PAA layer exhibit significant antibacterial activity. The carboxyl (¬-COOH) or the corresponding carboxylate groups (¬-COO-) interact with Cu2+ and Ag+ ions by formation of ionic bonds (¬-COO-Ag+ or 2 ¬-COO->Cu2+). Moreover, short exposure to light and temperature has reduced Cu2+ and Ag+ to Cu0 and Ag0. KW - Elektrospray Ionization KW - Silver nanoparticles KW - Adhesion PY - 2017 DO - https://doi.org/10.1080/01694243.2017.1315910 VL - 31 IS - 24 SP - 2641 EP - 2656 PB - Taylor & Francis CY - Adingdon AN - OPUS4-40506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -