Silica Nanotubes: Wetting and Diffusion Phenomena


Douglas S. English Department of Chemistry and Biochemistry, University of Maryland

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Nanoscale porous structures are attracting a great deal of interest due to their significant potential to biological and technological applications, including catalytic supports, biosensors or nanoscale containers. Silica nanotubes, in particular, are promising materials because of their naturally hydrophilic surface, which allows them to form colloidal suspensions in aqueous solvent without aggregation. Furthermore, the use of template-based synthesis methods allows easy production of monodisperse silica nanotubes and an important technological advantage of this approach is the ability to systematically change both the size and surface chemistry of the nanotube interior.

In order to use nanotubes as chemical nanocontainers, one must understand the transport properties occurring in the nanotube interiors including diffusion and wetting behavior under a variety of conditions. This can be especially important when nanotube cargo is weakly coupled with the tube interior, for example, by adsorption. Diffusion processes occurring on the nanotube interior surface are of fundamental significance for any application of nanotubes. Adsorption, diffusion, and wetting behavior will ultimately determine the success of applications employing template-synthesized silica nanotubes.

This entry discusses several examples that demonstrate some of the valuable applications of silica nanotubes including separations using nanotube-based membranes, selective functionalization of nanotube surfaces for the capture and concentration of target solutes and investigations of diffusion and wetting phenomena at the interior nanotube surfaces.