Thermoresponsive Triblock-Copolymers of Polyethylene Oxide and Polymethacrylates: Linking Chemistry, Nanoscale Morphology, and Rheological Properties
Thermoresponsive Triblock-Copolymers of Polyethylene Oxide and Polymethacrylates: Linking Chemistry, Nanoscale Morphology, and Rheological Properties
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DOI：
10.1002/adfm.202109010
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发表时间：
2021-11-23
影响因子：
19
通讯作者：
Cook, Michael T.
中科院分区：
文献类型：
--
作者：
da Silva, Marcelo Alves;Haddow, Peter;Cook, Michael T.
热可逆凝胶在加热时从自由流动的液态切换到弹性凝胶中间相，在冷却时显示相反的转变。虽然这种现象使这些先进材料在许多领域都具有很高的吸引力，但由于缺乏设计原则，定制流变性和转变温度的最佳材料的产生受到抑制。为了满足这一需求，我们制备了一个ABA共聚物库，其中“a”嵌段具有热响应行为，“B”嵌段为聚乙二醇。该文库评估了“A”化学的影响，探测了三种聚合物类别，以及A/B嵌段分子量对聚合物溶液中热诱导相变的影响。通过流变学与小角中子散射（SANS）耦合的探索阐明了纳米尺度上发生的温度依赖的分层自组装过程以及体流变学。这一过程揭示了凝胶状态下流变学和超胶体组合（球体、椭圆和圆柱体）之间的联系，并通过结构因素进一步探索了相互作用。确定了几个设计原则，以告知下一代热可逆凝胶的起源，以及在应用医疗保健技术的溶液状态下表现出热响应行为的新型材料。
Thermoreversible gels switch from a free-flowing liquid state to an elastic gel mesophase upon warming, displaying the reverse transition upon cooling. While this phenomenon makes these advanced materials highly attractive in numerous fields, the generation of optimal materials of tailored rheology and transition temperatures is stifled by the lack of design principles. To address this need, a library of ABA copolymers has been prepared with "A" blocks exhibiting thermoresponsive behavior and "B" blocks of poly(ethylene glycol). This library evaluates the effect of "A" chemistry, probing three polymer classes, and A/B block molecular weight on thermally-induced phase changes in solutions of the polymers. An exploration by rheometry coupled to Small-Angle Neutron Scattering (SANS) elucidates temperature-dependent hierarchical self-assembly processes occurring on the nanoscale as well as bulk rheology. This process deciphered links between rheology and supracolloidal assemblies (sphere, ellipses, and cylinders) within the gel state with interactions probed further via structure factors. Several design principles are identified to inform the genesis of next-generation thermoreversible gels, alongside novel materials exhibited thermoresponsive behavior in the solution state for use in applied healthcare technologies.