**14. Electrical conductivity of composite of PVA/PANI nanoparticles**

Polymers are commonly insulators as they have no significant mobile charges to serve the electrical conductivity. One of the requirements for polymers to exhibit good conductivity is the existence of π-electrons, which overlaps along the conjugated chain to form πconjugated band. The conductivity of conjugated polymers or pure polymers can be increased after suitable oxidization or reduction process (Kanazawa *et al*., 1979; Blythe, 1979) by doping or blending with charge donors of several organic groups (El-Sayed *et al*., 2003) like hydroxyl, amine, carboxylate, sulfonate, and quaternary ammonium (Blanco *et al.*, 2001) or by radiation induced doping (Park *et al*., 2002). In this work, the PVA was first blended with the organic monomer, AniHCl and then followed by irradiation to oxidize the monomer into the conducting PANI.

The conductivity of polymer composites, generally consist of free or weakly bound electronic and ionic charges and trapped ionic charges in the polymer matrix. The free charges are free to move in electrical field, independent of frequency and contribute to the direct current (dc) conductivity. While charge carriers that are trapped in the polymer matrix require alternating electric field at certain frequency to liberate the ions from one site to another site in succession by hopping mechanism and contribute to the alternating current (ac) conductivity. Realizing this, the electrical conductivity of un-irradiated and irradiated PVA will be measured and discussed first. This allows us to determine the conductivity values and identify the type of charge carriers in the un-irradiated and irradiated PVA before blending the PVA with AniHCl monomer at various concentrations and undergo irradiation.
