Surface patterning for the preparation of hierarchically porous thin films

ZELCER, A; WOLOSIUK, A; SOLER-ILLIA, GJAA

Porto Galinhas, Brasil

Conferencia; XVth International Sol-Gel Conference; 2009

International Sol-Gel Society

Hierarchically mesoporous thin films with micron-sized cavities were prepared by covering a carbonaceous exotemplate with ceramic mesoporous thin films, followed by removal of the templates. The templates were prepared by dewetting of a sucrose-surfactant solution, producing disk-like features of micron to submicron size. The localization of these templates is such that a large area of the substrate is covered when compared with other techniques like colloidal templating or nanosphere lithography. The method is accessible and convenient and can be used to pattern areas of several dm2. Ordered mesoporous SiO2[1], TiO2 and ZrO2 were deposited by EISA[2] over the templates using dip-coating, yielding a carbonaceous-ceramic macro and mesostructured thin film. Depending on the thickness of the ceramic layer, the mesopore arrangement was found to be severely influenced by the constraints imposed by the surface topology, leading to a different crystalline orientation of the pores[3]. This effect seems to be promoted by an anchoring effect on the highly curved rims of the disk-like templates. Removal of the carbonaceous templates by calcination yields macrocavities on the mesoporous thins films which preserve the substrate surface free from ceramic, providing an interesting alternative for mesoporous-based selective electrodes.  [1] The results on SiO2 were previously reported on: A. Zelcer, A. Wolosiuk, G.J.A.A. Soler-Illia J. Mater. Chem. 2009, DOI:10.1039/B902378J. [2] D. Grosso, F. Cagnol, G. J. A. A. Soler-Illia, E. L. Crepaldi, H. Amenitsch, A. Brunet-Bruneau, A. Bourgeois, C. Sanchez, Adv. Funct. Mater., 2004, 14, 309; C. J. Brinker, Y. Lu, A. Sellinger, H. Fan, Adv. Mater., 1999, 11, 579. [3] Y. Wu, G. Cheng, K. Katsov, S. W. Sides, J. Wang, J. Tang, G. H. Fredrickson, M. Moskovits, G. D. Stucky, Nat. Mater., 2004, 3, 816; B. Platschek, N. Petkov, T. Bein, Angew. Chem. Int. Ed., 2006, 45, 1134; M. Antonietti, G. A. Ozin, Chem. Eur. J., 2004, 10, 28.