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The blending of conducting polyaniline (PANI) with elastomers (natural rubber (NR) and acrylonitrile-butadiene rubber (NBR)) by a wet mixing process has been studied with the goal of fabricating flexible ultra thin conducting films. Good conductive properties were found for NR composite films with 30 wt% of HCl treated PANI and NBR composite films with 20 wt% of HCl treated PANI. There was a gradual decrease in surface resistivity with increasing PANI (HCl) concentration. The UV/VIS spectra indicated the presence of conjugated sequences of conducting polyaniline in the composite films. The FT-IR/ ATR results indicated the compatibility of HCl doped PANI with both NR and NBR and hence better mechanical properties, as indicated by an increase in the Young's modulus. Thus the conducting component acted simultaneously as reinforcement and conductive filler for both matrices. However the NBR composites became harder and more brittle with the increase in PANI concentration. The results have been correlated with swelling measurements confirming the formation of an interpenetrated network, which inhibits rubber solubilization. The method opens up a new technique for preparing stable conductive thin films of PANI using dopants such as HCl.

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Conducting polymers are finding new application areas in energy storage devices, optoelectronics, actuators etc. Iodine doped semiconducting prevulcanized natural rubber latex (RVNRL) is a potential candidate for many such applications. We had already demonstrated for the first time that pre-vulcanized NR latex can be doped by iodine to become electrically conducting and doping process is not affecting the flexibility or processability of the films. Synthesis and characterization of intrinsically electric conducting preculcanized natural rubber latex are briefly discussed. Further, dynamical mechanical properties of these doped RVNRL are reported. The glass transition (Tg) temperature of the chemically doped polyisoprene material was found to be shifted to higher temperature region with the iodine concentration. However, the mechanical properties are found to decrease at higher concentration of the dopant after showing an increasing trend as in the case of Tg at lower doping levels. An effort has also been made to explain this visibly contradictory behavior.