Observation of phase separated structure in siloxane sol-gel systems in a confined space

Abstract

Siloxane gel with co-continuous structure derived from methyltrimethoxysilane (MTMS) and tetramethoxysilane (TMOS) were synthesized in 2- and O-dimensional confined spaces by inducing spinodal decomposition during sol-gel transition. The resultant macroporous gel morphology was 3-dimensionally examined by a laser scanning confocal microscopy (LSCM). The depth profile of volume fraction of gel phase oscillated near both hydrophobic and hydrophilic glass surfaces due to the attractive interactions between phase-separating siloxane phase and surfaces and/or shrinkage during aging stage. In 0-D confined space, surprisingly fine but disordered TMOS-derived gel has formed in broadened composition rage while MTMS-derived gel did not.