Formation of Ethylene–Silica Nanofibers with Concentric Circular Mesopores Inside and Lamellar Mesopores on the Surfaces

Abstract

Ethylene-silica nanofibers with concentric circular mesopores inside and lamellar mesopores outside were prepared using stearyltrimethylammonium bromide (STAB) as template and (S)-beta-citronellol as a co-structure-directing agent. They were formed at the (S)-beta-citronellol/STAB molar ratio range of 3:1 to 4:1. Field emission scanning electron microscopy and transmission electron microscopy images taken after different reaction times revealed a phase transition from hexagonal to lamellar phase on the surface of the organic-inorganic hybrid silica nanofibers. The nanofibers with concentric circular pore channels were proposed to be formed from spherical micelles. With increasing the (S)-beta-citronellol/STAB molar ratio from 0.5:1 to 5:1, the morphology changed from short hexagonal rod to long nanofiber, and then to shrunk multilamellar vesicle. Moreover, 1,4-phenylene-silica nanofibers and nanoparticles with concentric circular mesopores inside and lamellar mesopores outside were also prepared.