Highly porous polysilsesquioxane networks via hydrosilylative polymerization of macrocyclic oligomeric silsesquioxanes

The 12- and 24-membered macrocyclic oligomeric silsesquioxanes were synthesized and hydrosilylative polymerization of the macrocyclic oligomeric silsesquioxanes was carried out to access cross-linked polysilsesquioxane networks. Polymerizable monomers were obtained with the high yields of more than 94% and bear vinyl groups and silicon-hydrogen bonds, which can be employed to promote their self-cross-linking hydrosilylative homomerization to access the polysilsesquioxane networks. The results show the presence of unreacted Si-H bonds and vinyl groups is associated with the steric hindrance resulting from the formation of rigid and bulk cross-linking networks. The polysilsesquioxane network shows absorption and no significant porosity and the small size of macrocyclic oligomeric silsesquioxanes is unfavorable to the formation of highly porous polyesquioxane.