Triple Stimuli-Responsive Amphiphilic Glycopolymer

Triple stimuli (temperature/pH/photo)-responsive amphiphilic glycopolymer, poly(2-(dimethylamino)ethyl methacrylate-co-6-O-methacryloyl-1,2,3,4-di-O-isopropylidene-D-galactopyranose)-b-poly(4-(4-methoxyphenylazo) phenoxy methacrylate) [P(DMAEMA-co-MAIpGP)-b-PMAZO] was synthesized by atom transfer radical polymerization, followed by the hydrolysis of MAIpGP groups, resulting in the target product poly(2(dimethylamino)ethyl methacrylate-co-6-O-methacryloyl-D-galactopyranose)-b-poly(4-(4-methoxyphenylazo) phenoxy methacrylate) [P(DMAEMA-co-MAGP)-b-PMAZO]. The composition, moleculer weight, and moleculer weight distribution of the resultant polymers were characterized by H-1 NMR and gel permeation chromatography. The micelles formed in aqueous solutions were simulated by various chemical and physical stimuli and characterized by dynamic light scattering, transmission electron microscopy, and UV-vis spectroscopy. It was found that the glycopolymer is responsive to three different types of stimulus (light, temperature, and pH). The poly(2(dimethylamino) ethyl methacrylate) segments give thermo- and pH-responsiveness. The presence of the azobenzene moiety endows the block copolymer to exhibit light-responsiveness due to its reversible trans-cis isomerization conversion. The triple stimuli-responsive glycopolymer micelles can simulate biomacromolecues in vivo/in vitro environment and can be expected to open up new applications in various fields. (C) 2014 Wiley Periodicals, Inc.