Semiconducting composite of chalcone-bridged polythiophene and titania, its ammonia vapor sensing property

Thiophene based chalcone linked monomer, 1, 3-di (thiophen-2-yl) prop-2-en-1-one (DTPN), its polymer (PDTPN) and the composite of the polymer with titania (TiO2) were synthesized under optimized reaction conditions. The structure of the monomer, polymer and the composite were characterized using 1H, 13C NMR, FT-IR, SEM, XRD, TGA and UV–visible spectral techniques. The monomer and the polymer possess reversible redox characteristics. The DC electrical conductivity at room temperature as well as at high temperature showed the semi conducting nature of the polymer and the composite. The variation of DC conductivity with temperature and the isothermal stability at various temperatures revealed Arrhenius type of behavior of the materials. The polymer (PDTPN) and the composite (PDTPN–TiO2) showed significant ammonia-sensing property at room temperature. Contact angle measurement disclosed that undoped and I2 doped polymers are hydrophobic while the polymers doped with p-TSA and HCl possess adjustable wetting characteristics. The theoretical evaluation of the material reveals the semi-conducting characteristics, the total charge density and the mechanism of ammonia interaction. This study proposes that the polymer, PDTPN and its composite with TiO2 can be used in electrical and electronic applications as well as in ammonia sensing.