Self-assembled multilayer films based on functionalized poly(thiophene)s

We study the layer-by-layer assembly and properties of polyelectrolyte multilayers containing cationic and anionic polythiophene derivatives, poly-2-(3-thienyloxy)propyltriethylammonium chloride (PTPA), poly(thiophene-3-acetic acid) (PTAA), and poly(sodium-2-(4-methyl-3-thiehyloxy)ethane sulfonate) (P-SMTE). These polymers were synthesized by chemical oxidation with FeCl3 and soluble in aqueous media. Two types of multilayers have been prepared by sequential adsorption of polyanions and polycations on charged surfaces: PTPA/PTAA and PTPA/P-SMTE. The linear relationship of the UV-vis adsorption spectra and QCM observed in these multilayer systems indicated that each layer was successfully deposited to form layer-by-layer films. FT-IR results also revealed that the multilayer structure was formed by electrostatic interaction.