Both graphene and Cloisite 30B nanosheets are widely employed to modify the crystalline structure and piezoelectic properties of polyvinylidene fluoride (PVDF). Due to the similarity in the geometry of these nanoparticles a comparative study is reported to find the stems of difference in their effects on crystalline structure of PVDF. Scanning electron microscopy (SEM) of these composites showed that large and wide graphene particles are dispersed in PVDF matrix whereas their thickness is well below 100 nanometers. Meanwhile, a careful inspection of SEM micrographs of Cloisite 30B loaded composites revealed existence of smaller particles with almost the same particles thicknesses. Both techniques of Fourier transform infrared (FT-IR) spectroscopy and wide angle X-ray diffraction (WXRD) witnessed changes in the crystalline structure of PVDF. The overall finding was that Cloisite 30B improves the polar beta phase of PVDF crystals, whereas a revers effect was found in the presence of graphene nanosheets. These observations were accounted for by differences in surface geometry and surface free energy (surface and interfacial tensions). Based on the data available for surface properties of these two nanosheets it was found that surface properties of Cloisite 30B is very close to those of PVDF, whereas the surface properties of graphene are far from those of PVDF. Also a lower interfacial tension was found to be active in PVDF-Cloisite 30B system compared to that operative in PVDF-graphene system. An intimate interface along with proper surface texture led to higher content of PVDF’s beta crystals in case of Cloisite 30B nanocomposite. پرونده مقاله

In this study, we aimed to enhance the electrical conductivity of polymeric layers for potential applications in organic electronics such as sensors and capacitors. Electrically conductive polythiophene (PTh) and polypyrrole (PPy) layers were deposited on a poly methyl methacrylate (PMMA) substrate using an in-situ chemical oxidative deposition method with FeCl3 as a catalyst and acetonitrile and deionized water as solvents. To further improve conductivity, multi-layer PTh and PPy, in the presence of carbon nanotubes (CNT), were applied on the PMMA substrate. The reaction times for synthesizing PTh and PPy were optimized to be 12 and 20 minutes, respectively, based on electrical properties. Fourier-transform infrared spectroscopy (FTIR) was used to identify the different components of the conductive polymers on the PMMA substrate. The morphology and thickness of the layers were investigated using scanning electron microscopy (SEM). The electrical conductivity of the layers was measured using a four-point probe device. The highest electrical conductivity of 100.93 S/cm was achieved for the two-layer poly pyrrole-polythiophene/CNT coating on the PMMA substrate. These findings demonstrate the potential of this multi-layer conductive coating for various organic electronic applications. پرونده مقاله

An extensive review of the literature showed that both graphene and Cloisite 30B nanosheets are widely employed to modify the crystalline structure and piezoelectic properties of polyvinylidene fluoride (PVDF). Due to the similarity in the geometry of these nanoparticles a comparative study is reported to find the stems of difference in their effects on crystalline structure of PVDF. Scanning electron microscopy (SEM) of these composites showed that large and wide graphene particles are dispersed in PVDF matrix whereas their thickness is well below 100 nanometers. Meanwhile, a careful inspection of SEM micrographs of Cloisite 30B loaded composites revealed existence of smaller particles with almost the same particles thicknesses. Both techniques of Fourier transform infrared (FT-IR) spectroscopy and wide angle X-ray diffraction (WXRD) witnessed changes in the crystalline structure of PVDF. The overall finding was that Cloisite 30B improves the polar beta phase of PVDF crystals, whereas a revers effect was found in the presence of graphene nanosheets. These observations were accounted for by differences in surface geometry and surface free energy (surface tension and interfacial tension). Based on the data available for surface properties of these two nanosheets it was found that surface properties of Cloisite 30B is very close to those of PVDF, whereas the surface properties of graphene are far from those of PVDF. Also a lower interfacial tension was found to be active in PVDF-Cloisite 30B system compared to that operative in PVDF-graphene system. An intimate interface along with proper surface texture led to higher content of PVDF’s beta crystals in case of Cloisite 30B nanocomposite. پرونده مقاله