Poly(3-thiophene acetic acid) (P5TAA) was synthesized using chemical procedures. The structure, surface and morphology of these water-soluble polythiophenes were determined by introducing pH-responsive carboxylic acid groups at the 3-position of thiophene ring and doing FT-IR spectra, SEM and TGA analyses. Based on the neutralization reaction obtained when using sodium hydroxide at various concentrations, the authors suggest that the local conformational changes that occur from the aggregated state to the extended state of the polymer main chain of P5TAA can be attributed to the pH change in the solution. The observed results are explained in terms of the rigid hydrophobic main chain, the interaction between hydrophilic charged groups and the nature of the conjugated polymer.