Journal of Polymer Science Part A: Polymer Chemistry, Vol.51, No.18, 3829-3839, 2013
Controlled synthesis of new amphiphilic glycopolymers with liquid crystal grafts
A cholesterol-based liquid crystal monomer, diethylene glycol cholesteryl ether acrylate (DEGCholA), has been successfully polymerized by atom transfer radical polymerization (ATRP) for the first time. Appropriate experimental conditions to control the polymerization of DEGCholA have been investigated using a model initiator (ethyl 2-bromoisobutyrate) in tetrahydrofuran (THF) or toluene at 60 degrees C. Well-controlled ATRP of DEGCholA was obtained using N,N,N',N',N ''-pentamethyldiethylenetriamine as ligand in THF at 60 degrees C. These conditions were then applied to initiate the ATRP of DEGCholA from multifunctional macroinitiators based on dextran. Using a protection/deprotection synthetic scheme, novel graft glycopolymers (Dex-g-PDEGCholA) have been synthesized. The mesomorphic properties of DEGCholA, PDEGCholA, and Dex-g-PDEGCholA have been studied by thermal polarizing optical microscopy, differential scanning calorimetry, and X-ray scattering. PDEGCholA and Dex-g-PDEGCholA show an interdigitated smectic A phase (SmAd) between T-g (similar to 30 degrees C) and around 170 degrees C. (C) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3829-3839
Keywords:amphiphilic;atom transfer radical polymerization (A;cholesterol;dextran;glycopolymer;graft copolymers;liquid crystal copolymer;polysaccharides