Preparation of Mesoporous Silica-Polymer Composites to Introduce Dual Porosity in Monolithic Silica

Three dimensional porous materials are the best choice for such applications as catalysis, adsorbents and sensors. However, diffusion controlled surface interaction is a limiting factor in the use of conventionally unimodal nanoporous monolithic solids. Herein, both solid polymer fibers and soluble block copolymers were added to the organosilane precursor solution to prepare a composite material. Dual porosity obtained after controlled burning off of all polymeric templates. Scanning electron microscopy (SEM) and BET/BJH gas adsorption analysis confirmed very well ordered porosity in micro and nanoscale originated from microfibers and soluble polymer self-assembly, respectively. Erosion tests on samples prepared by P123 block copolymer in presence of polymer microfibers confirmed that polyacrylonitrile (PAN) is the best choice in comparison with polyurethane (PU) and cellulose fibers. According to this test, both PAN and cellulose are suitable pore making materials in micrometer scale for solution based adsorption or catalysis application, but PU does not pass the erosion test.

Keywords:

Mesoporous silica , Dual porosity , Monolith , Catalysis , Composite gel