Solid-State Synthesis and Photocatalytic Activity of Polyterthiophene Derivatives/TiO₂ Nanocomposites

Poly(3,4-propylenedioxy-2,2':5',2"-terthiophene)/TiO₂ and poly(3,4-(2,2-dimethylenepropylenedioxy)-2,2':5',2"-terthiophene)/TiO₂ nanocomposites were synthesized by a simple solid-state method. Additionally, the poly(3,4-propylenedioxy thiophene)/TiO₂ and poly(3,4-2,2-dimethylenepropylenedioxythiophene)/TiO₂ nanocomposites were synthesized in a similar manner for comparison. The structure and morphology were characterized by Fourier transform infrared (FTIR), ultraviolet-visible (UV-Vis) absorption spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM). The photocatalytic activities of the nanocomposites were examined through the degradation processes of a methylene blue (MB) solution under UV light and sunlight irradiation. The results of FTIR and UV-Vis spectra showed that the composites were successfully synthesized by solid-state method and the poly(3,4-propylenedioxy-2,2':5',2"-terthiophene)/TiO₂ and poly(3,4-(2,2-dimethylenepropylenedioxy)-2,2':5',2"-terthiophene)/TiO₂ nanocomposite had a higher oxidation degree and conjugation length than others. The results also indicated that the TiO₂ had no effect on the crystallinity of composites, but was well embedded in the polymer matrix. Additionally, the highest degradation efficiency of 90.5% occurred in the case of the poly(3,4-propylenedioxy-2,2':5',2"-terthiophene)/TiO₂ nanocomposite.