Preparation of Helical Mesoporous Ethenylene-silica Nanofibers with Lamellar Mesopores on Their Surface

The morphologies and pore architectures of mesoporous ethenylene-silica were controlled using cetyltrimethylammonium bromide (CTAB) as template and (S)-beta-citronellol as a co-structure-directing agent under basic conditions. When the (S)-beta-citronellol/CTAB molar ratios are in the range of 0.75-2.0, helical nanofibers were obtained. With increasing the (S)-beta-citronellol/CTAB molar ratio, the lengths of the nanofibers increases. Lamellar mesopores were identified on the surfaces of the nanofibers prepared in the (S)-beta-citronellol/CTAB molar ratio range of 1.5-2.0. At the (S)-beta-citronellol/CTAB molar ratio of 2.5 : 1, nanoparticles with nanoflakes on the surfaces were obtained. The field emission scanning electron microscopy images taken after different reaction times indicated that the helical pitches of the nanofibers decreased with increasing the reaction time. Helical 1,4-phenylene-silica and methylene-silica nanofibers were also prepared. The results indicated that the morphologies and pore architectures of the obtained organic-inorganic hybrid silicas are also sensitive to the hybrid silica precursors. Helical ethenylene-silica nanofibers with lamellar mesopores on their surfaces can be also prepared using the mixtures of CTAB and racemic citronellol within a narrower citronellol/CTAB molar ratio range.