Thermoresponsive poly(di(ethylene glycol) methyl ether methacrylate)-ran-(polyethylene glycol methacrylate) graft copolymers exhibiting temperature-dependent rheology and self-assembly
Thermoresponsive poly(di(ethylene glycol) methyl ether methacrylate)-ran-(polyethylene glycol methacrylate) graft copolymers exhibiting temperature-dependent rheology and self-assembly
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DOI：
10.1016/j.molliq.2021.117906
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发表时间：
2022-01-08
影响因子：
6
通讯作者：
Cook, Michael Thomas
中科院分区：
文献类型：
--
作者：
da Silva, Jessica Bassi;Haddow, Peter;Cook, Michael Thomas
具有刷式结构的接枝共聚物含有聚（乙二醇）甲基丙烯酸酯与“热敏”单体共聚，使聚合物具有较低的临界溶液温度。首先，探索了热敏聚合物的化学结构，合成了含有N-异丙基丙烯酰胺、N，N-二乙基丙烯酰胺和二甘醇甲基醚甲基丙烯酸酯的材料。含二（乙二醇）甲基丙烯酸甲醚（DEGMA）的热响应接枝共聚物表现出接近生理条件的相变温度（约30℃）。探讨了聚合物组成的影响，包括分子量、peg -甲基丙烯酸酯（PEGMA）末端功能和PEGMA/DEGMA比值。相对分子质量与相行为表现出复杂的关系，相对分子质量较低的体系在较低的临界溶液温度（LCST）上表现得更稳定，但存在下限。PEGMA/DEGMA进料能够控制转变温度，较高的PEGMA比例提高了热转变。结果表明，末端带有甲氧基官能团的PEGMA在LCST上方形成稳定的胶体结构，而末端带有羟基官能团的PEGMA在加热后一般形成两相沉积体系。两种基于degma的热响应接枝聚合物poly(PEGMA（7)-ran-DEGMA(170)）和poly(PEGMA（1)-ran-DEGMA(38)）具有有趣的温度依赖流变性能，在加热时转变为粘性状态。这些材料可以应用于形成热增稠系统，在暴露于人体热量时改变流变性。(C) 2021作者。Elsevier B.V.出版
Graft copolymers with brush-type architectures are explored containing poly(ethylene glycol) methacrylates copolymerized with "thermoresponsive" monomers which impart lower critical solution temperatures to the polymer. Initially, the chemical structure of the thermoresponsive polymer is explored, synthesizing materials containing N-isopropyl acrylamide, N,N-diethyl acrylamide and diethylene glycol methyl ether methacrylate. Thermoresponsive graft-copolymers containing di(ethylene glycol) methyl ether methacrylate (DEGMA) exhibited phase transition temperature close to physiological conditions (ca 30 degrees C). The effect of polymer composition was explored, including molecular weight, PEG-methacrylate (PEGMA) terminal functionality and PEGMA/DEGMA ratios. Molecular weight exhibited complex relationships with phase behavior, where lower molecular weight systems appeared more stable above lower critical solution temperatures (LCST), but a lower limit was identified. PEGMA/DEGMA feed was able to control transition temperature, with higher PEGMA ratios elevating thermal transition. It was found that PEGMA terminated with methoxy functionality formed stable colloidal structures above LCST, whereas those the hydroxy termini generally formed two-phase sedimented systems when heated. Two thermoresponsive DEGMA-based graft polymers, poly(PEGMA(7)-ran-DEGMA(170)) and poly(PEGMA(1)-ran-DEGMA(38)), gave interesting temperature-dependent rheology, transitioning to a viscous state upon heating. These materials may find application in forming thermothickening systems which modify rheology upon exposure to the body's heat. (C) 2021 The Authors. Published by Elsevier B.V.