Size-selective separation of macromolecules by nanochannel titania membrane with self-cleaning (Declogging) ability

We report on a simple and self-organizing process for the fabrication of TiO₂ nanochannel membranes with a channel width of 8-10 nm that can be used for size selective separation of macromolecules (proteins). The membrane, consisting of self-aligned oxide channels, is formed by complete anodization of a thin Ti foil under specific electrochemical conditions in a glycerol-phosphate electrolyte. Due to self-cleaning properties of TiO ₂, clogged membranes (for example due to extended use) can easily be fully reopened and thus are reusable. As the TiO₂ after anodic formation directly contains anatase crystallites (the most photoactive TiO ₂ crystal form) no thermal treatment of the membrane is required (avoiding the danger of thermally induced cracking).