Synthesis of periodic mesoporous organosilica with remarkable morphologies

Periodic mesoporous organosilicas (PMOs) with remarkable surface patterns a nd shapes such as rope, spiral, gyroid, spheroid, etc. were synthesized. Th ese samples were characterized by X-ray diffraction (XRD), N-2 sorption mea surement, scanning electron microscope, and transmission electron microscop e (TEM). From the XRD pattern and TEM image, octadecyltrimethylammonium (OD TMA)-PMO with hexagonal symmetry was identified. The pore diameter and BET surface area of ODTMA-PMO are 33 Angstrom and 799 m(2) g(-1), respectively. When synthesized at 95 degreesC for 6 h under a static condition, ODTMA-PM O with rope-shape dominates. With longer reaction time for 21 h, the amount of wormlike shaped aggregates increased. With agitation, the rope shaped m orphology with low curvature disappeared dramatically, while most of produc ts exhibited a variety of morphologies with a high curvature. The generatio n of these morphologies could be interpreted partly in terms of the degree of curvature and the accretion type induced by various topological defects. (C) 2001 Elsevier Science B.V. All rights reserved.