Mesoporous Hybrid Thin Films: from One Pot Synthesis to Selective Membranes

PAULA C. ANGELOMÉ; ALEJANDRA CALVO; PAULA Y. STEINBERG; FEDERICO J. WILLIAMS; GALO J. A. A. SOLER-ILLIA

Tours

Conferencia; Hybrid Materials 2009 - First International Conference on Multifunctional, Hybrid and Nanomaterials; 2009

Mesoporous materials is an expanding field, where the possibility of generating tuned pore arrays with controlled size and interconnection permits to design complex nanoreactor cavities. 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). The introduction of organic or metallo-organic functions on the surface of mesopores is a step forward towards the creation of complex chemical systems with tuned reactivity. 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 such as R = phenyl, aminopropyl, cianopropyl, vinyl, etc (M1-xSixO2-x/2Rx). Block copolymer Pluronic F127 was used as the template, leading cubic structures with pores of about 10 nm diameter. In selected cases a second function was added by post grafting, in order to obtain multifunctional materials. The MHTF were characterized by means of FTIR, XPS, UV-vis, electronic microscopy, X ray diffraction and reflectometry. The effect on acid base behavior of the R group was evaluated as a function of the matrix composition and the presence of a second organic group. The application of these kind of materials as perm-selective membranes was tested by cyclic voltammetry measurements. The results demonstrated that it is possible to synthesize, in only one synthesis step, a membrane that allows or not the permeation of a probe as a function of the medium pH. The obtained results can be modified by the presence of a second function.