Studies on Highly Porous Hybrids Prepared by a Novel Fast Gellation Process Under Ambient Pressure

摘要

Supercritical drying of hydrolyzed alkoxysilanes is a typical method for making aerogel-type of highly porous materials.However,multiple step process is beinbg required for surface modificatio of pore walls to avoid collapsing effect caused by drying shrinkage.We wish to describe in here a novel fast,single step sol-gel route for the preparation of ultra high porous materials.Commercially available hydrogensilsesquioxane was used as precursor in this approach,leading through a simple,single step process to gels within minutes and thus without any further surface modification needed.Systematic studies of this novel fast gellation process were carried out through careful variation of experimental conditions to gain porosity control and enable improved design of this class of ultra high porous monolithic materials.