Nano-assembled supramolecular films from chitosan-stabilized gold nanoparticles and cobalt(II) phthalocyanine

In this work, we report the synthesis and characterization of gold nanoparticles (AuNPs) stabilized with chitosan (Chit), as well as the capability of this material to form multilayer films with cobalt(II) tetrasulfonated phthalocyanine (CoTsPc). The new hybrid material based on Chit-AuNPs and CoTsPc was characterized by several techniques, and the electrochemical properties of an ITO (indium tin oxide) electrode modified with Chit-AuNPs and CoTsPc were investigated. Chit-prevented AuNPs (diameter of 6.0 nm) agglomeration, forming a colloidal suspension that was stable for months. The interaction between the AuNPs and Chit-molecules occurs mainly through the CH2 and NH 3+ groups from Chit. Supramolecular interaction was observed for multilayer films of Chit-AuNPs/CoTsPc, and the AuNPs influenced the redox properties of CoTsPc. The presence of the nanoparticles not only increased the electroactive area of the electrodes, but also the rate of charge-transfer, suggesting that this material is a very promising candidate for further applications in electrochemical devices. © 2013 Sociedade Brasileira de Química.