Desenvolvimento de filmes nanoestruturados à base de polianilina e nanopartículas de óxido de zinco para futuras aplicações em sensores eletroquímicos de dopamina

Abstract

Semiconductive materials such as metallic nanoparticles have been incorporated into the thin film structure as an alternative to improve their performance against the selectivity and sensitivity of these devices. In this sense, this study aimed to the development of thin films produced from zinc oxide nanoparticles (ZnONPs) intercalated with polyaniline (PANI) which is an environmentally compatible conducting polymer that has aroused enormous interest due to its properties electrochemical, anticorrosive and electrochromic. After studies on the best structure and deposition sequence of the layers was selected for characterization of the ZnONPs / PANI bilayer. The films were characterized by the electrochemical technique of Cyclic Voltammetry in potassium phosphate buffer 0.1 mol L-1, pH 2.1, and also by spectroscopy in the UV-Vis region. When comparing the adsorption sequence of two ZnONPs / PANI and PANI / ZnONPs bilayers with PANI / PANI, the synergism between the materials was observed, where ZnONPs acts to protect PANI against its acid degradation. The ZnONPs / PANI film, containing 1 bilayer, showed the best results of electrochemistry, reversibility and electrochemical stability when compared to the PANI / ZnONPs film. The growth kinetics of the ZnONPs / PANI film were monitored by spectroscopy in the UV-Vis region showing characteristic behavior of self-regulating systems. At a later stage, the ZnONPs / PANI film developed here was subjected to a detection test of the neurotransmitter Dopamine (DA) at 400 μmol L-1. The results showed a 108.7% increase in current density values for the film in the presence of the neurotransmitter. Another important aspect to be emphasized is that the film is stable electrochemically, under the experimental conditions used here, being a very important feature for the study of this film in sensing tests. The objective of this work is to carry out speed test, atomic force microscopy, chronoamperometry and square wave voltammetry, study the effects of interferences and test other neurotransmitters.