Biomimetic surface patterns of layered aluminum oxide mesophases templated by mixed surfactant assemblies

Aluminum-based mesophases templated by both dodecyl sulfate (DS) and alkyl alcohols (AA), CnH2n+1OH (n = 4-18), or dilauryldimethylammonium (DDA) have been synthesized by the homogeneous precipitation method using urea. Coincorporation of DS and DDA or AA with n greater than or equal to 6 leads to the formation of such a stable lamellar mesophase as to hamper the transition from layer to hexagonal structure observed in the AA- or DDA-free system. The interlayer spacing of the lamellar mesophases increases to 3.9-5.0 nn from 3.5 nm for the AA- or DDA-free system. Biomimetic patterns such as cone-shaped or terraced hollows and domed-scales also occur on the surface of lamellar particles formed in the DS/AA with n greater than or equal to 12 or DS/DDA mixed systems, whereas no specific surface patterns are observed in the shorter chain alcohol mixed or DDA-free systems.