Preparation and characterization of LbL films based on graphene oxide nanoparticles interacting with 3-n-propylpyridinium silsesquioxane chloride

Graphene oxide (GO) obtained by electrochemical exfoliation method was used to prepare a composite with the inorganic polymer, 3-n-propylpyridinium silsesquioxane chloride polymer, SiPy+. This composite (SiPy+(GO)) was applied as polyelectrolyte to form LbL films with nickel tetrasulfophthalocyanine (NiTsPc4−) as polyanion. The absorbance of the NiTsPc4− Q bands linearly increased with the number of deposited bilayers (SiPy+(GO)/NiTsPc4−)n LbL films. From the graphics of absorbance as a function of the number of bilayers, it was possible to observe that the amount of NiTsPc4− deposited on the FTO substrate is higher to the SiPy+(GO)/NiTsPc4− than SiPy+/NiTsPc4− films, as a consequence of the effective π–π interaction between the graphene and phthalocyanine molecules. The Raman spectra of the film with graphene oxide, SiPy+(GO)/NiTsPc4− showed the GO “D” bands at 1339cm−1, and the “G” bands at 1556cm−1. The presence of GO in the SiPy+(GO)/NiTsPc4− film was confirmed by the presence of “2D” band at 2686cm−1, which is not observed in the SiPy+/NiTsPc4− film. Cyclic voltammetric and EIS studies showed that the presence of graphene oxide nanoparticles in the film configuration considerably increased its conductivity when compared to the film without GO (SiPy+/NiTsPc4−) which favors its application for the development of electrochemical sensors.