Reversible Formation of Interpenetrating Polymer Network Structure in Organic-Inorganic Polymer Hybrids

A new strategy to prepare organic-inorganic polymer hybrids having interpenetrating polymer network (IPN) structure is presented. Polymer hybrids were synthesized from poly(2-methyl-2-oxazoline) having coumarin moieties as reversibly photo-crosslinkable side groups (4). It was found that the concentration of acid catalyst for sol-gel reaction of tetramethoxysilane (TMOS) was essential to obtain transparent and homogeneous polymer hybrids. Reversible photo-dimerization of coumarin groups took place in the polymer hybrids by the irradiation of light with different wavelengths. The resulting polymer hybrids are IPN of organic gel and silica gel. Solvent-resistant property of the polymer hybrids was improved by formation of the IPN structure.