Preparação e caracterização de nanocompósitos de poli(3-hexiltiofeno)-TiO2

Abstract

In this work, crystalline titanium dioxide (TiO2) nanoparticles were synthesized and incorporated in a poly (3-hexylthiophene) (P3HT) matrix by means of an in-situ polymerization process. The microwave-assisted synthesis using titanium tetrachloride in aqueous media promoted the formation of particles smaller than 10 nm, which thermodynamically ensured the formation of the anatase crystalline phase. The heat treatment at 400 ° C resulted in a sample containing interconnected nanoparticles, having a heterogeneous morphology and a specific surface area of (457 ± 32) m2 g4 and total pore volume of (0.67 ± 0.05) cm3g4. This sample was effective in the photodegradation of the methylene blue dye, which showed the potential of the nanoparticles to act as a photocatalyst with a suitable half-life for electron-hole pairs. In a second part of the work, P3HT/TiO2 nanocomposites containing 1.0; 2.0 and 5.0% m / m in TiO2 were prepared by in situ polymerization. Transmission electron microscopy images allowed to confirm the presence of submicron agglomerates and individual TiO2 nanoparticles inserted in the P3HT matrix. The insertion of the nanoparticles promoted a small reduction of the polymer regiorregularity and small variations of the optical absorption/emission properties, especially the P3HT/TiO2 2% m/m sample, which was more promising. Systematic increases in the properties: glass transition temperature, crystallization temperature and melting temperature occurred with the insertion of the TiO2 nanoparticles in the P3HT matrix. Cyclic voltammograms showed variations in the oxidation potential values for the nanocomposites compared to P3HT sample. All the samples showed semi-reversible behavior at scan rates studied. The results presented in this work suggest that there is feasibility of using the nanocomposites prepared in energy conversion and storage devices.