Cyclodextrins in polymer synthesis:: Free radical polymerization of a N-methacryloyl-11-aminoundecanoic acid/β-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-CD) as a host, yielding the water-soluble monomer N-methacryloyl-11-aminoundecanoic acid/beta-CD pseudorotaxane (2). This pseudorotaxane was polymerized radically in an aqueous medium by use of the water soluble azoinitiator 2,2'-azobis(N,N'-dimethylenisobutyramidine). The obtained poly(N-methacryloyl-11-aminoundecanoic acid) (3) was insoluble in water because of a nearly quantitative unthreading of the cyclodextrin during the polymerization. It was found that the precipitation polymerization of N-methacryloyl-11-aminoundecanoic 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 conditions.