Synthesis and growth mechanism of starfish-like anatase TiO2 nanocrystal with outstanding antibacterial property and super-hydrophobicity

A facile synthetic method in terms of a two-stage sol-gel hydrothermal approach using double surfactants, cetyltrimethylammonium bromide (CTAB) and triblock copolymer PEO106-PPO70-PEO106 (F127), incorporated with diethylamine (DEA) is proposed, for the first time, to synthesize a kind of starfish-like anatase TiO2 nanocrystals with V-, semi-star-, and star-shapes. The formation, growth, and phase transition of titania crystals were investigated via a X-ray diffraction (XRD), a scanning electron microscopy (SEM), and a transmission electron microscopy (TEM). The results indicate that the crystallinities, sizes, morphologies and structures of TiO2 nanocrystals are strongly dependent on the reaction times of 1, 3, 6, 9, 12 and 18 h. The formation and growth mechanisms of the V-shaped, semi-star, and star anatase TiO2 crystals are thus discussed. The F127-CTAB double surfactants and DEA play as shape-controlling agents in tuning the desired shapes of the anatase TiO2 nanocrystal. Results show that the starfish-like anatase TiO2 nanocrystals possess excellent antibacterial activity and an outstanding super-hydrophobicity.