LCST 행동에 영향을 미치는 PDMA의 건축 변경

Abstract

A series of poly(dimethylacrylamide) (PDMA) bottlebrushes with various side chain length tailoring on the backbone were synthesized by the “grafting-from” approach using reversible addition-fragmentation chain transfer polymerization (RAFT). ATRP was employed to synthesize poly(2-hydroxyethyl methacrylate) (PHEMA) with high molecular weight (degree of polymerization, DP = 500) , followed by reacting with EMP to yield PHEMA500-EMP as a macro-CTA (backbone). N,N-dimethylacrylamide (DMA) was grafted from macro-CTA to yield a series of bottlebrushes (PHEMA500-EMP-g-PDMA) with various side chain lengths. Bottlebrushes were characterized by gel permeation chromatography (GPC) and 1H NMR. The molecular weight distribution was low (Mw/Mn = 1.2-1.3). Transmittance spectra of the aqueous solutions of linear homopolymer and bottlebrush polymer of PDMA at 650 nm were measured by Uv-vis for comparing the effect of change in architecture on LCST behavior of PDMA with the same degree of polymerization. The results demonstrate that PDMA is dramatically affected by changes in architecture and PDMA bottlebrushes exhibited LCST below 100 oC.