Preparation of polyaniline free standing film by controlled processing and its transport property

Polyaniline(emeraldine base : EB) free standing films with different degree of cross-linking prepared from NMP solution were stretch-oriented at 110 ∼ 180°C up to 110 = 4 then doped with 1N HCl. Free standing films of polyaniline doped with various functionalized acid such as camphorsulfonic acid (HCSA), dodecylbenzenesulfonic acid (HDBSA), methane sulfonic acid(HMSA) etc. were prepared in various solvents such as o-chlorophenol, chloroform, etc. Processing conditions were determined by measuring UV/Vis spectra of solution. Films prepared from these solutions showed the conductivities of 10−1 ∼ 220S/cm. To investigate the effect of molecular weight on the properties of polyaniline films, high molecular weight polyaniline (Mw ∼ 309,000) was synthesized at ∼ −30°C. It was found that mechanical property, crystallinity, conductivity of the films depend on the drying process and type of solvent. Transport properties for various polyaniline free standing fims will be discussed from the results of DC, microwave conductivity and thermopower measurements.