곁가지에 다양한 길이의 알코올 그룹을 지닌 고분자들의 저임계 용액온도 민감성 제어

Abstract

하이드록시 그룹을 지닌 온도민감형 고분자들이 원자전이라디칼중합법(ATRP)과 클릭반응(click reaction)에 의해 합성되어졌다. 고분자들의 분자량과 분자량 분포도는 gel permeation chromatography(GPC)에 의하여 얻어졌고, 고분자들의 분자량은 잘 제어되었으며 분자량 분포도도 낮게 유지되었다. 클릭반응의 효율은 <TEX>$^1H$</TEX> NMR spectroscopy에 의해 얻어졌으며, 높은 효율을 나타내었다. 고분자 사슬 곁가지의 아민 그룹의 종류와, 치환된 알코올 그룹의 종류에 따라 저임계 용액 온도(LCST)의 제어가 가능했다. Thermoresponsive polymers were successfully synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide and alkynes (click chemistry). Poly(2-hydroxyethyl methacrylate) (PHEMA) was synthesized by ATRP, followed by introduction of alkyne groups using pentynoic acid, leading to HEMA-alkyne. Homopolymers having secondary amine groups, tertiary amines with hydroxyethyl and hydroxypropyl groups were synthesized by adding 2-azido-N-ethyl-ethanamine, 2-[(2-azidoethyl)amino]ethanol, and 2-[(2-azidoethyl)amino]propanol, respectively, to the PHEMA-alkyne backbone using click chemistry. Molecular weight (MW), molecular weight distribution (MWD), and click reaction efficiency were determined by gel permeation chromatography (GPC) and <TEX>$^1H$</TEX> NMR spectroscopy. The transmission spectra of the 1.0 wt% aqueous solutions of the resulting polymers at 650 nm were measured as a function of temperature. Results showed that the lower critical solution temperature (LCST) could be easily controlled by the length of the hydroxyalkyl groups.