POLYANILINE - CONFORMATIONAL-CHANGES INDUCED IN SOLUTION BY VARIATIONOF SOLVENT AND DOPING LEVEL

The reduced viscosity of mixtures of polyaniline (emeraldine base, EB) and d,l-camphorsulfonic acid (HCSA) in solutions of m-cresol or chlor oform (or in mixtures of these solvents) was investigated. Viscosity m easurements as a function of (a) increasing m-cresol content in the mi xed solvent for a fully protonated 'EBH(+)/CSA(-)' polymer, and (b) in creasing protonation level of EB by increasing amounts of HCSA in m-cr esol, indicate that the fully protonated polymer adopts a maximized ex panded molecular conformation in a good solvent such as m-cresol. Thes e results suggest that the greatly different conductivities obtained f or 'EBH(+)/CSA(-)' films cast from m-cresol or chloroform solutions re sult primarily from their different molecular conformations in these s olvents.