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), C n H 2 n +1 OH ( 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 ≥ 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 nm 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 ≥ 12 or DS/DDA mixed systems, whereas no specific surface patterns are observed in the shorter chain alcohol mixed or DDA-free systems.