Oxidation of aniline with ammonium peroxodisulfate in aqueous solution
s containing poly(3-sulfonato-4-hydroxystyrene) gave polymer alloys (o
r polymer blends) with a general composition of )[-CH2-CH(C6H3.OH.SO3-
)-](x)(H2SO4)(y).zH(2)O}(n). Their electrical conductivities depended
on the composition and Varied between 10(-5) and 0.5 S cm(-1) at 300 K
. The polyaniline salts were soluble in water and exhibited an electro
nic absorption band characteristic of emeraldine salts at 800 nm. The
corresponding alkaline solutions showed a band due to emeraldine bases
at 600 nm. These bands showed a pH dependence that is a consequence o
f an interchain interaction between two kinds of polymer chains. A pol
ymer with x=0.4, y=1.2 and z=3.6 was soluble enough to observe EPR spe
ctra, whose pH dependence showed that, with increasing pH, deprotonati
on occurs at polarons prior to deprotonation at bipolarons.