Substituted polyaniline/chitosan(PANIs/Ch) composites were chemically synthesized by using ammonium peroxydisulfate as oxidant and characterized by measurements of conductivity, FTIR, UV-vis, SEM and TGA techniques. FTIR spectra of the composites revealed that there is a strong interaction between substituted polyanilines and chitosan. Among the substituted polyaniline/chitosan composites synthesized. poly(N-ethylaniline)/chitosan PNEANI/Ch has the highest conductivity with a value of 1.68 x 10(-4) S/cm. The P2EANI/Ch composite exhibited higher thermal stability than the other composites. SEM images of the composites showed an agglomerated granular morphology of substituted polyaniline particles coated on the surface of chitosan. (C) 2008 Elsevier Ltd. All rights reserved.