Electrophoretic deposition of poly[3-(3-N,N-diethylaminopropoxy)thiophene] and composite films

Poly[3-(3-N,N-diethylaminopropoxy)thiophene] (PDAOT) was prepared by oxidative polymerization and investigated by ultraviolet (UV), Raman and nuclear magnetic resonance (NMR) spectroscopies. Protonated PDAOT was dissolved in water or ethanol/water mixtures and deposited by cathodic electrophoretic deposition (EPD) on conductive substrates. Film thickness was varied in the range of 0–5μm by controlling the deposition voltage and deposition time. PDAOT was found to form strong supramolecular interactions with single-walled carbon nanotubes (SWNTs), allowing the formation of stable and concentrated nanotube dispersions, which were used for the formation of composite PDAOT–SWNT films by EPD. Furthermore, introduction of ZnO particles to the PDAOT solutions also allowed the formation of PDAOT–ZnO composite films by EPD. The composition of the films was varied by changing the concentration of SWNTs and ZnO in the suspensions. The dispersion of ZnO particles was improved using protonated dopamine (DA) as a dispersant. The deposits were studied by X-ray analysis (XRD), thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction and scanning electron microscopy (SEM).