Cyclodextrins in polymer synthesis: Free radical polymerization of a N-methacryloyl-11-aminoundecanoic acid/beta-cyclodextrin pseudorotaxane in an aqueous medium

The relatively hydrophobic monomer N-methacryloyl-11-aminoundecanoic acid ( 1) was incorporated as a guest into the cavity of beta-cyclodextrin (beta-C D) as a host, yielding the water-soluble monomer N-methacryloyl-11-aminound ecanoic acid/beta-CD pseudorotaxane (2). This pseudorotaxane was polymerize d radically in an aqueous medium by use of the water soluble azoinitiator 2 ,2'-azobis(N,N'-dimethylenisobutyramidine). The obtained poly(N-methacryloy l-11-aminoundecanoic acid) (3) was insoluble in water because of a nearly q uantitative unthreading of the cyclodextrin during the polymerization. It w as found that the precipitation polymerization of N-methacryloyl-11-aminoun decanoic acid/beta-CD pseudorotaxane in water occurred much faster compared to the polymerization of the uncomplexed N-methacryloyl-11-aminoundecanoic acid in a homogeneous DMSO/water solution (4/1 v/v) under similar conditio ns.