Lee Joonhee, McGrath Alaina J, Hawker Craig J, Kim Byeong-Su
Department of Chemistry, School of Natural Science, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Korea.
Materials Research Laboratory, University of California Santa Barbara, Santa Barbara, California 93106, United States.
ACS Macro Lett. 2016 Dec 20;5(12):1391-1396. doi: 10.1021/acsmacrolett.6b00830. Epub 2016 Dec 2.
Thermoresponsive polymers exhibiting lower critical solution temperatures (LCSTs) in aqueous solution have garnered considerable attention for the development of smart materials. Herein, we report the synthesis and properties of pH-tunable thermoresponsive poly(ethylene oxide) (PEO)-based functional polymers bearing pendant amine groups with varying cloud points. Well-defined poly(ethylene oxide--allyl glycidyl ether) (P(EO--AGE)) copolymers were prepared via controlled anionic ring-opening copolymerization of ethylene oxide (EO) with 10 mol % of a functional allyl glycidyl ether (AGE) comonomer. Facile, modular thiol-ene click chemistry was then employed to introduce a library of different aminothiols as side chains to the initial P(EO--AGE) copolymer. Depending on the nature of the pendant amine groups (primary amine, dimethylamine, and diethylamine) and the hydrophobicity of the side chains (ethyl, propyl, and hexyl), the cloud points could be tuned from 44-100 °C under different pH conditions. This is the first systematic investigation into the effect of PEO copolymer side chains on cloud point, which opens up the opportunity to make new thermoresponsive polymers for a variety of smart material applications.
在水溶液中表现出较低临界溶液温度（LCST）的热响应性聚合物在智能材料的开发中受到了广泛关注。在此，我们报道了具有不同浊点的、带有侧链胺基的pH可调热响应性聚环氧乙烷（PEO）基功能聚合物的合成及性能。通过环氧乙烷（EO）与10 mol%的功能性烯丙基缩水甘油醚（AGE）共聚单体进行可控阴离子开环共聚反应，制备了结构明确的聚（环氧乙烷-烯丙基缩水甘油醚）（P(EO-AGE)）共聚物。然后采用简便的模块化硫醇-烯点击化学方法，将一系列不同的氨基硫醇作为侧链引入到初始的P(EO-AGE)共聚物中。根据侧链胺基的性质（伯胺、二甲胺和二乙胺）以及侧链的疏水性（乙基、丙基和己基），在不同pH条件下，浊点可在44 - 100°C之间调节。这是首次对PEO共聚物侧链对浊点影响的系统研究，为开发用于各种智能材料应用的新型热响应性聚合物提供了机会。
