TY - JOUR A1 - Fahmy, Alaa A1 - Kolmangadi, Mohamed Aejaz A1 - Schönhals, Andreas A1 - Friedrich, J. T1 - Structure of plasma‐deposited copolymer films preparedfrom acrylic acid and styrene: Part III sulfonation andelectrochemical properties N2 - Acrylic acid-styrene copolymer films were deposited plasma-chemically more gently using the pulsed plasma mode instead of the continuous mode, with linear and some slightly branched chains and marginal crosslinking. Then, the styrene unit of copolymers was wet-chemically sulfonated by chlorosulfuric acid. On exposure to air, the formed 4-chlorosulfonic acid groups hydrolyze to sulfonic acid groups (-SO3H). FTIR, XPS and broadband dielectric spectroscopy were employed to characterize the composition, the structure, the functional groups, and the electrochemical performance for the copolymers. A high concentration of sulfonic acid-containing groups was obtained in the sulfonated PS sample. The values of the DC conductivity DC for the sulfonated sample of the AA/S copolymer are ca. five orders of magnitude higher than that of the not-sulfonated copolymer materials. KW - Plasma Polymers KW - Electrolyte membrane PY - 2022 U6 - https://doi.org/10.1002/ppap.202100222 SP - 1 EP - 12 PB - Wiley VHC-Verlag AN - OPUS4-54539 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 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-526794 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 - Fahmy, Alaa A1 - Schönhals, Andreas T1 - Reaction of CO2 gas with (radicals in) plasma-polymerized acrylic acid (and formation of COOH-rich polymer layers) N2 - In contrast to most of the existing literature on plasma polymerization of acrylic acid (AA), not only the chemical structure and film thickness of the deposits were studied, but also a new way to obtain COOH-rich surfaces. This is an important aspect when applying the obtained coatings for biomedical and electronics applications. Therefore, acrylic acid/CO2 polymer films with a thickness of ca. 150 nm were deposited in the pulsed plasma regime onto polyethylene and aluminium as organic and inorganic substrates. Their structure–property relationships were studied in dependence on the mixture ratio of acrylic acid monomer and CO2 gas. The influence of the CO2 gas on the regularity and functionality of plasma deposited poly(acrylic acid) (PAA) was studied in detail using bulk-sensitive (dielectric spectroscopy and Fourier transforms infrared spectroscopy) as well as surface-sensitive methods such as X-ray photoelectron spectroscopy. For a clear identification of the functionality of the deposited films, the COOH groups were estimated after derivatization with trifluoroethanol by XPS measurement as well as by the quantitative analysis of the FTIR data. Results show, in presence of a small amount of CO2 gas within the acrylic acid plasma, a structure of poly(acrylic acid) with high concentration of COOH groups was obtained. However, the excess of CO2 gas in the plasma chamber leads to fragmentation of the monomer or/and degradation of the layer which is already deposited. A polymer network is obtained with an increasing abundance of branched groups for AA/CO2 with increasing CO2 gas in the mixture. KW - Poly(acrylic acid) KW - Plasma polymerization KW - COOH rich surfaces PY - 2016 U6 - https://doi.org/10.1002/ppap.201500128 SN - 1612-8850 VL - 13 IS - 5 SP - 499 EP - 508 PB - Wiley-VCH Verlag CY - Weinheim AN - OPUS4-36058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 U6 - 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 - Abdel-Wakil, W. A1 - Fahmy, Alaa A1 - Kamoun, E. A1 - Hassan, W. A1 - Abdelhai, Q. A1 - Salama, T. T1 - A New Route for Synthesis of Polyurethanevinyl Acetate Acrylate Emulsions as Binders for Pigment Printing of Cotton Fabrics N2 - Herein, two polyurethane oligomers were successfully synthesized using a prepolymer mixing process. The prepolymers were synthesized based on the step-growth addition polymerization of polypropylene glycol, Methylene diphenyl diisocyanate and 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate. Isopropanol was functioned as the isocyanate blocking agent. Thereafter, different terpolymer emulsions were prepared by the emulsion graft copolymerization with the vinyl acetate monomer in presence of 2-ethylhexyl acrylate as a vinyl monomer. The chemical structures of the synthesized oligomeric monomers were probed by FTIR spectroscopy and found to vary with the content of acrylic monomer used in the oligomer synthesis phase (i.e.hydroxyethyl acrylate or hydroxyethyl methacrylate). The topography, thermal stability, and particle size of terpolymers were investigated by SEM, TGA, and zeta potential, respectively. The TGA results demonstrated marked enhancement in thermal stability of the synthesized terpolymers up to ca. 600°C, which was concurrent with enhanced surface homogeneity and film properties as evidenced by the SEM images. These terpolymers showed also property enhancement as binders for textile pigment printing in terms of rubbing resistance, color strength and fastness to washing when compared to the commercial binders. These judgments would provide a new competent synthesis route by introducing polyurethane acetate vinyl acrylate as the binder for use in pigment printing of cotton fabrics. KW - Vinyl monomer KW - Polyurethane acetate vinyl acrylate KW - Surface coating KW - Terpolymer KW - Textile binder PY - 2020 U6 - https://doi.org/10.21608/ejchem.2020.21712.2292 VL - 63 IS - 3 SP - 1063 EP - 1073 AN - OPUS4-52300 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 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-523013 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, Alaa A1 - Abou-Saied, M. A1 - Helaly, H. A1 - El-Dessoki, F. A1 - Mohamed, T. T1 - Novel PVA/Methoxytrimethylsilane elastic composite membranes: preparation, characterization and DFT computation N2 - A modified composite membranes (PVA/SiOH/SiOC) were made via solution-casting process using different 1:1, 1:2, 1:3 and 1:4 volume ratios of polyvinyl alcohol (PVA):methoxytrimethylsilane (MTMS). Moreover, FT-infrared and energy-dispersive X-ray spectroscopy (EDX) were mesured to account for the network structural rearrangements involving silicon within PVA matrices. The addition of MTMS has improved the thermal and mechanical properties of the composite membranes as compared to pristine PVA. In addition, the crystallinity and the morphological changes of PVA/MTMS composites was studied using X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. Three structures were suggested based on trimethyl silanol (I) wet out condensation (II and III) with the dopped PVA followed by and H-bonding interactions (IV). The outcomes of B3LYP/6-31G(d) frequency calculations favors a three-dimensional SiOC linked network (III). Nevertheless, EDX reveals, the 3D SiOC links are not observed on the surface of composite membranes, however, is found dominant in the bulk, [(CH3)3SiOCH2CH2CH2O]n. Moreover, the solubility, density, and refractive index of the synthesized composites were measured and found depended on the ratio of PVA in the composite membranes. The current results are compared with that published earlier including dimethoxydimethylsilane at the same conditions. KW - Polymer composites KW - DFT calculations KW - Elastic membrane KW - Methoxytrimethlsilane KW - Polyvinyl alcohol PY - 2021 U6 - https://doi.org/10.1016/j.molstruc.2021.130173 VL - 1235 SP - 130173 PB - Elsevier B.V. AN - OPUS4-52302 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 U6 - 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, Alaa A1 - Omar, Hassan A1 - Szymoniak, Paulina A1 - Schönhals, Andreas A1 - Friedrich, J. T1 - Structure of plasma deposited acrylic acid‐allyl alcohol copolymers N2 - Copolymer thin films with two types of functional groups have excellent performance as sensors, for example. The formation and deposition of allyl alcohol‐acrylic acid copolymer films by pulsed high frequency plasma is a complex process. As usual, the chemical composition of the top surface of the films was investigated by XPS and FTIR measurements. Furthermore, contact angle measurements with water were used to characterise the hydrophilicity and wettability of the polymer films. After plasma deposition, a significant decrease in functional groups (OH and COOH) was observed compared to the classically copolymerised equivalent. The remaining functional groups, i.e. the majority of these groups, were sufficient for application as sensor layers. Segmental mobility and conductivity, important for sensor applications, were analysed by broadband dielectric spectroscopy. KW - Plasma Polymerization PY - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-578349 SN - 1612-8850 SP - 1 EP - 14 PB - Wiley online library AN - OPUS4-57834 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -