Improving pore exposure in mesoporous silica films for mechanized control of the pores

Abstract

A novel hierarchically structured material consisting of a mesoporous silica film, prepared by a vapor-phase infiltration method that is microscopically patterned and using a reactive wet-stamping technique, is reported. The two-dimensional hexagonal mesostructure consists of tubular pores of approx 2.4 nm in diameter that are aligned in a particular direction. The micropatterns, 1.5 μm wide strips oriented perpendicular to the direction of the nanopores and separated from each other by 1.5 μm gaps, were etched in such a manner so as to enable multiple regions of accessibility to the nanopores that would otherwise not be easy to access. The nanopore accessibility and orientation were confirmed by infiltration of the nanopores with a fluorescent polymer, resulting in a polarization of the emission. After the etching process, mechanically interlocked molecules that act as gatekeepers were attached to the nanopore openings. Trapping and on-command release of luminescent probe molecules were demonstrated in these micro-patterned mesoporous silica films. © 2010 Elsevier Inc. All rights reserved.