Preparation And Characterization of Various Porous Silica Materials Via Self-Assembly of Surfactants In Strong Acid Condition

Abstract

The exquisite formation of liquid-crystal-like structure through formed molecular complexes among silicon alkoxide,amphiphilic or cationic surfactant,and protonated water in strong acidic condition is an effective approach for the synthesis of various porous silica materials. The size,charge,and molecule structures of surfactants in mesophase formation at acidic aqueous condi-tion are important structure-determining factors which are closely related with surfactant packing parameter,g=V/a I.That enables us to explain and predict prepared product structure in this system,and design the geometry of various porous materials for specific applications. These various porous silica materials are able to synthesize via ionic,covalent,or hydrogen bonding interac-tions between the hydrophilic surfaces of flexible rod-or worm-like micelles to assemble an inorganic oxide framework. High order porous structures with uniform diameter ranging from 2-7.5㎚ have been obtained by varying the size and structure of the surfactant molecules. The synthesis of silica-surfactant porous nanostructures has been studied under various acidic conditions.