Optical, mechanical, and electrical studies of polymer composites based on charge transfer complex of phenothiazine–iodine with poly(vinyl chloride)

Charge transfer complex (CTC) of phenothiazine and iodine (1:2 molar ratio) was prepared by solvent evaporation method in diethyl ether and its composite with poly(vinyl chloride) was prepared in benzene by diffusion method. Infra-red spectra showed overlapped peaks for both components and intensity of individual component was proportional to feed ratio. Optical photographs and scanning electron microscopy of composites showed template growth and connectivity in insulator matrix was proportional to wt% of CTC. Mechanical strength of composites was found to increase with wt% of PVC. The current–voltage study showed percolation threshold of 8 wt% of CTC. The temperature dependence of conductivity showed semiconducting nature of the materials. Transport property of charges were explained by regression analysis of σdc vs. T−1/1+n data and meets the basis for the Mottʹs 2D, 3D variable range hopping or thermoionic emission model, depending on temperature and wt% of CTC content. The impedance spectroscopy was performed between 40 Hz–100 kHz range. Circuit elements consists only combination of resistance and capacitance, which showed homogeneous nature of composites. Thermoelectric factor ‘S’ was also evaluated and has value of <1 at 303 K in all cases.