We report our results on ac conductivity and dielectric constant measu
rements at 10 kHz on polyaniline and derivatives of polyaniline having
alkyl ring-substituents. A comparison with de conductivity is made to
gain further insight into the conduction mechanism. The room temperat
ure de and ac conductivities are similar; however, deviations at lower
temperatures characteristic of conduction mechanisms typical of varia
ble range hopping are observed. This deviation is larger for samples h
aving greater disorder. Disorder also suppresses the temperature depen
dence of the dielectric constant.