Estudo do sistema ternário baseado em polianilina, grafeno e matriz acrílica aplicado em sistemas termoelétricos

Abstract

Thermoelectric materials have drawn attention due to their ability to convert thermal energy into electricity, enabling the use of waste energy and offering a green option for power generation. Organic thermoelectric materials (OTE) such as polyaniline are promising fillers due to their low cost, low thermal conductivity, flexibility, as well as scalable and non-toxic manufacturing. However, the efficiency of OTE materials is still lower than inorganic composites. In recent years, composites of conducting polymers and carbon nanomaterials such as graphene have been developed, providing a promising way to increase the power factor (PF). Graphene is a nanomaterial with excellent electrical, mechanical and thermal properties. It is believed that polyaniline can be integrated into graphene through π-π stacking interactions, helping to achieve efficiency in TE properties. In this research work, it is aimed to develop a thermoelectric system based on an acrylic matrix with the coaddition of graphene and polyaniline, based on the hypothesis that the synergistic effect allows percolation at low charge concentration. Polyaniline/graphene nanocomposites were obtained by in situ polymerization of aniline in the presence of different concentrations of graphene. The ternary systems were obtained by adding acrylic matrix, polyaniline and graphene in mechanical mixing. Structural and morphological characterization was performed, allowing to evaluate the influence of graphene insertion on PANI morphology and crystallinity, as well as to infer about the presence of π-π interaction between the chains, through the reduction of the gap and increase of the electrical conductivity with the presence of graphene. The measured Seebeck coefficient reaches a maximum value of -17.02μVK-1 and the highest power factor obtained was 4.94μWm- 1K-2 for the ACR/PANI sample, indicating improved electrical properties and a material with promising power factor (PF) and thermoelectric properties to OTE systems reported in the literature containing PANI.