Multiscale Templating of Siloxane Gels via Polymerization-Induced Phase Separation

By combining the micellar templating in nanometer-scale with the polymerization-induced phase separation in micrometer-scale, we can synthesize monolithic silica or silsesquioxane gel materials with hierarchical well-defined macropores and shape-controlled mesopores. Depending on the mechanism of enhancing micellar-templating of siloxane oligomers, macroframeworks containing long-range-ordered cylindrical mesopores with different degrees of order have been produced. Alkylene-bridged silicon alkoxides can also be prepared into similarly hierarchical porous structures with broadened variations in framework morphology. These examples demonstrate the versatility of using phase-separation in micellar-templated gelling systems to obtain well-defined macroporous structures.