3 research outputs found
Temperature dependent charge transport mechanisms in carbon sphere/polymer composites
Carbon spheres (CS) with diameters in the range were prepared
via hydrolysis of a sucrose solution at and later annealed in
at The spheres were highly conducting but difficult to process into
thin films or pressed pellets. In our previous work, composite samples of CS
and the insulating polymer polyethylene oxide (PEO) were prepared and their
charge transport was analyzed in the temperature range
Here, we analyze charge transport in CS coated with a thin polyaniline (PANi)
film doped with hydrochloric acid (HCl), in the same temperature range. The
goal is to study charge transport in the CS using a conducting polymer (PANi)
as a binder and compare with that occurring at CS/PEO. A conductivity maxima
was observed in the CS/PEO composite but was absent in CS/PANi. Our data
analysis shows that variable range hopping of electrons between polymeric
chains in PANi-filled gaps between CS takes on a predominant part in transport
through CS/PANi composites, whereas in CS/PEO composites, electrons travel
through gaps between CS solely by means of direct tunneling. This difference in
transport mechanisms results in different temperature dependences of the
conductivity.Comment: 7 pages, 6 figure
Optimization of PVDF-TrFE Based Electro-Conductive Nanofibers: Morphology and In Vitro Response
In this study, morphology and in vitro response of electroconductive composite nanofibers were explored for biomedical use. The composite nanofibers were prepared by blending the piezoelectric polymer poly(vinylidene fluoride–trifluorethylene) (PVDF-TrFE) and electroconductive materials with different physical and chemical properties such as copper oxide (CuO), poly(3-hexylthiophene) (P3HT), copper phthalocyanine (CuPc), and methylene blue (MB) resulting in unique combinations of electrical conductivity, biocompatibility, and other desirable properties. Morphological investigation via SEM analysis has remarked some differences in fiber size as a function of the electroconductive phase used, with a reduction of fiber diameters for the composite fibers of 12.43% for CuO, 32.87% for CuPc, 36.46% for P3HT, and 63% for MB. This effect is related to the peculiar electroconductive behavior of fibers: measurements of electrical properties showed the highest ability to transport charges of methylene blue, in accordance with the lowest fibers diameters, while P3HT poorly conducts in air but improves charge transfer during the fiber formation. In vitro assays showed a tunable response of fibers in terms of viability, underlining a preferential interaction of fibroblast cells to P3HT-loaded fibers that can be considered the most suitable for use in biomedical applications. These results provide valuable information for future studies to be addressed at optimizing the properties of composite nanofibers for potential applications in bioengineering and bioelectronics