Estudo de filmes automontados de compostos de níquel na presença do cloreto de 3-n-propil silsesquioxano e surfactantes

Abstract

This thesis describes the interactions between the nonionic surfactant p-(1,1,3,3- tetramethylbutyl)phenyl-polyethylene glycol (Triton X) and sodium dodecyl sulfate (SDS) with the cationic polymer 3-chloride-n-propylpyridinium silsesquioxane (SiPy) in the presence of nickel phthalocyanine tetrasulfonate (NiTsPc), which they were evaluated using surface tension and viscosity measurements. The effects of these interactions were also studied when these polyelectrolytes were transferred to thin films by the LbL technique on conductive substrate (indium doped tin oxide - ITO), quartz and silicon. It has been observed by UV-Vis absorption spectroscopy there is a synergistic effect provided by the interaction of the cationic polyelectrolytes (SiPy / surfactant) and anionic (NiTsPc) polyelectrolytes in the LbL films. Spectroscopic techniques, such as, FTIR and Raman, and electrochemical techniques, electrochemical impedance and cyclic voltammetry, it was observed that there is a coexistence of mixed and pure micelles. The adsorption of these aggregates plays an important role on the surface of the LbL films. The synthesis and characterization of nickel hydroxide nanoparticles, in their α phase, stabilized by the SiPy polymer, and by the zwitterionic surfactant 3- (1-alkyl-3 - imidazolium) propane sulfonate was realized. The surfactant ImS3-14 was chosen for its preferential interaction with anions, making it an excellent stabilizer for the growth of the Ni(OH)2 nanoparticles. The formation of the aggregates was characterized by dynamic scattering of light (DLS) and zeta potential to determine size and charge, respectively. After the synthesis of the nanoparticles, they were deposited by the LbL technique on several substrates. The growth of the films was accompanied by UV-VIS and their characterization was evaluated by FTIR, Raman, AFM and MEV-FEG techniques. The electrochemical characteristics of the films were studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS).