Synthesis of 6-armed amphiphilic block copolymers with styrene and 2,3-dihydroxypropyl acrylate by atom transfer radical polymerization

The controlled free radical polymerization of (2,2-dimethyl-1.3-dioxolan-4-yl)methyl acrylate (DMDMA) was achieved by atom transfer radical polymerization (ATRP) in tetrahydrofuran (THE, 50%, v/v) solution at 90°C with the discotic six-functional initiator, 2,3,6,7,10,11-hexakis(2-bromobutyryloxy) triphenylene (HBTP). The 6-armed polyDMDMA with low polydispersity index (Mw/Mn = 1.52-1.32) was obtained. The copolymerization of DMDMA with styrene (St) using 6-armed polySt-Br as macroinitiator was carried out, and the GPC traces of the copolymers with different segment compositions and narrower polydispersity (1,21-1.24) were synthesized and subsequent hydrolysis of the acetal-protecting group in 1 N HCI THF solution produced poly[St-b-(2,3-dihydroxypropyl)acrylate] [poly(St-b-DHPA)], which was verified by IR and NMR spectroscopy.