Preparation of amphiphilic polysilsesquioxane by grafting of block copolymer of acrylamide monomers

The polysilsesquioxane having dithiocarbamate groups was utilized for the graftation of N-isopropyl-acrylamide (NIPAM) and N,N-dimethylacrylamide (DMAA) under thermal polymerization conditions. The controlled graft polymerization through RAF-F process proceeded effectively to give several kinds of block copolymer of NIPAM and DMAA without formation of gel product, in which the sequence and the number of the monomer units were changed. The introduction of the block copolymers provided an amphiphilic property to the polysilsesquioxane. The hydrophilic property, which was shown as solubility in water and contact angle, was affected by the sequence and the number of the monomer units in the graft chain. Furthermore, as the expected property due to a hydrophobic aggregation of NIPAM units, the contact angles of the grafted polysilsesquioxanes measured at 60 degrees C were larger than those at 23 degrees C.