This paper describes a unique process of polymerization in an aqueous mediu
m of an anilinium-dodecyl benzene sulfonic acid (DBSA) complex obtained by
reacting aniline with DBSA prior to polymerization, The typical properties
of the complex, appearing as fine needles, have been characterized and its
polymerization behavior in the presence of DBSA upon addition of ammonium p
eroxydisulfate in an aqueous medium was investigated by visual color inspec
tion, UV-VIS spectroscopy and pH measurements. The polymerization process w
as interrupted at different stages and polyaniline (PANI) powders were obta
ined by precipitation with methanol. The powders morphology was investigate
d using scanning electron microscopy (SEM) and their electrical conductivit
y was measured on compression molded strips. UV-VIS and pH measurements sho
w that the average oxidation state of the formed PANI chains vary during po
lymerization from doped pernigraniline to doped emeraldine and correlate wi
th the dispersion's color. In the beginning of the polymerization course, t
he SEM studies show agglomerates consisting of spherical PANI particles. As
polymerization proceeds, the voids among these particles are filled, formi
ng a smooth surface of the PANI agglomerates, Simultaneously, the conductiv
ity of the PANI powders increases with the polymerization time. (C) 1999 El
sevier Science S.A. All rights reserved.