“Mesoporous Hybrid Thin Films: from One Pot Synthesis to Permselective Membranes”

ALEJANDRA CALVO, PAULA C. ANGELOMÉ, MARIA JOSELEVICH, OMAR AZZARONI, FEDERICO WILLIAMS Y GALO J. A. A. SOLER-ILLIA.

Bariliche

Workshop; US-Argentina Workshop on Nanomaterials. Bariloche 2009; 2009

Mesoporous hybrid thin films (MHTF) present a great interest for their potential in domains such as optics, electronics, chemical sensing, catalysis, separation, etc. These materials are synthesized by an Evaporation Induced Self Assembly process, which combines sol-gel chemistry and self-assembly of an organic counterpart (polymer or surfactant templates). In this work we have synthesized MHTF by the one pot method, based on M = Ti, Si, Zr oxides and containing a variety of organic functions R = aminopropyl (M1-xSixO2-x/2Rx). Block copolymer Pluronic F127 was used as the template, leading cubic structures with pores of about 10 nm diameter. The MHTF were characterized by means of FTIR, XPS, UV-vis, TEM, X ray diffraction and reflectometry. The acid base behavior and chemical reactivity of the amine group in MHTF was studied. We found that there is a clear relationship between the radio of amine/ammonium and the oxide composition. Furthermore, it is only the 20% of the amine functionalities available for reaction. The application of these materials as perm-selective membranes was tested by cyclic voltammetry. The results demonstrated that it is possible to synthesize, in one-pot, a membrane that allows or not the permeation of a probe as a function of the medium pH. Moreover, we showed how to tailor this permselectivity by changing the electrostatic nanoenvironment of the pores through the covalent functionalization with polyelectrolyte brushes.