Diffusion in coiled pores - learning from microrelease and microsurgery.

The anisotropic diffusion in coiled pore systems of SBA-3-type microparticles has been studied by the release of guest molecules. The diffusion turns out as an example of the influence of hierarchical structuring on physical properties. Two modes of diffusion, associated with transport along and across the mesopores, can be identified and measured using optical microscopy. Redistribution between the two modes has been achieved by mesopore opening using two methods of "microsurgery"-either focused ion beams (FIB) or mechanical tools. The particles trimmed by FIB have revealed risks of misinterpretation of sample preparation with this tool. Instead of pure pore opening, the cutting by FIB resulted in simultaneous sealing of the mesopores.