Enhancement of conductivity in polyaniline-[poly(vinylidene chloride)-co-(vinyl acetate)] blends by irradiation

In this study we have prepared conductive poly(aniline), (PANI) blends with poly(vinylidene chloride-co-vinyl acetate), [P(VDC-co-VAc)] copolymer with varying compositions using gamma radiation to induce conductivity. A number of blends with different compositions were prepared by solution casting followed by irradiation in a Co-60 gamma cell to different doses up to 800 kGy. Electrical conductivity of the blends was measured before and after irradiation using a four-probe technique. Increasing radiation dose resulted in an increase of 9 orders of magnitude in the conductivity of P(VDC-co-VAc)/(PANI) films reaching 0.1 S/cm at 500 kGy and beyond this dose a decrease was observed. Effect of film thickness on conductivity of the blends was investigated and a slight increase of an order of magnitude was observed on increasing the film thickness from 50 to 200 mu m. It was also observed that PANI blends exhibited a stretch dependent small increase in conductivity. The conductivity of the irradiated films was found to be stable for up to 12 months under ambient conditions. (C) 2010 Elsevier Ltd. All rights reserved

Radiation induced dehydrochlorination as an in-situ doping technique for enhancement of the conductivity of polyaniline blends

In our earlier studies we have shown that acid doping in PANI/PVC blends can be achieved by radiation induced HCl release from PVC parts. In order to enhance radiation-induced acid doping process in PANI blends we have prepared solution cast films of PANI with the copolymers of vinylidene chloride with vinyl acetate and vinyl chloride. Homogeneous films obtained from these binary systems as well as from PANI/PVC blends were exposed to gamma rays under ambient conditions. The increase in the conductivity of initially non-conducting films was significant, reaching values of 10(-2) S/cm from initial values of 10(-7) S/cm upon irradiation to 500 kGy dose. Chemical changes leading to relatively high conductivities were investigated by FT-IR spectroscopy by following the changes taking place in 1149 cm(-1) and 814 cm(-1) bands which are indicative of conductivity and chlorine binding in polyaniline. (c) 2005 Elsevier B.V. All rights reserved

Glucose recognition capabilities of hydroxyethyl methacrylate-based hydrogels containing poly(ethylene glycol) chains

A configurational biomimetic imprinting technique was used to prepare recognition sites for glucose in copolymers of 2-hydroxyethyl methacrylate (HEMA) and methacrylic acid (MAA) prepared with crosslinking agents containing poly(ethylene glycol) (PEG). We report on the structure, diffusive, and recognition characteristics of these gels, the effect of the type and ratio of crosslinking agent, as well as the template/comonomer ratios on glucose binding ability. The highest equilibrium glucose binding was found as 2.67 mg/g dry polymer when PEG monomethacrylate (PEGMMA) was used in combination with tetra ethylene glycol dimethacrylate (TEGDMA) (50%) as a crosslinking agent. (c) 2007 Wiley Periodicals, Inc. J Appl Polym Sci 103: 432441,200