Controlling Polymer Material Structure during Reaction-Induced Phase Transitions
Controlling Polymer Material Structure during Reaction-Induced Phase Transitions
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DOI：
10.1021/accountsmr.3c00071
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发表时间：
2023-07-24
影响因子：
14.6
通讯作者：
Hickey，Robert J.
中科院分区：
文献类型：
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作者：
Hickey，Robert J.
结论：生命系统是由一系列生物聚合物和矿物质组成的，但在材料特性上表现出巨大的多样性。广泛的特性，如增强的皮肤和骨骼的机械性能或来自结构着色的响应性光学性能，是材料的多尺度，层次结构的结果。材料和高分子化学领域利用平衡概念来模拟自然界中复杂材料的结构。然而，实现自然系统中的显着特性需要超越平衡的观点。另一种方法来创建具有多尺度结构的材料是从动力学的角度来处理这个问题，并利用化学过程来驱动相变。这个帐户的特点是我们小组的一个活跃的研究领域，反应诱导相变（RIPT），它使用化学反应，如聚合，诱导软材料系统的结构变化。取决于相变的类型（例如，微相对大相分离），所产生的状态变化将发生在不同的长度尺度（例如，nm−μm），从而决定了材料的结构。例如，在聚合过程中最初在单体混合物中原位形成嵌段共聚物或均聚物将分别驱动纳米尺度或宏观尺度转变。具体而言，将讨论利用反应驱动相变的三个不同实例：1）从嵌段共聚物原位聚合物接枝，2）多尺度聚合物纳米复合材料，和3）刘易斯加合物驱动相变。所有这三个领域都强调了通过聚合或特定化学结合的化学变化如何导致相变，从而导致纳米和多尺度变化。利用动力学化学过程来促进和控制材料结构，而不是在热力学框架内组织预先合成的分子，聚合物或纳米颗粒，是一个越来越感兴趣的领域。在聚合物材料中捕获非平衡态主要集中在聚合物链构象的观点，其中合成的聚合物受到不同的热和加工条件。反应动力学和聚合速率对最终聚合物材料结构的影响开始被认为是获得通过热力学手段不可用的不同形态的新方法。此外，聚合物材料结构的动力学控制并不特定于聚合，而是包括诱导形态转变的任何化学反应。决定材料结构的动力学驱动过程直接影响广泛的领域，包括分离膜、生物分子凝聚物、细胞流动性以及聚合物和胶体的自组装。使用动力学原理（如RIPT）推进聚合物材料合成，为决定材料结构和性能开辟了新的可能性，超出了传统自组装技术目前可用的范围。
ConspectusLiving systems are composed of a select number of biopolymers and minerals yet exhibit an immense diversity in materials properties. The wide-ranging characteristics, such as enhanced mechanical properties of skin and bone or responsive optical properties derived from structural coloration, are a result of the multiscale, hierarchical structure of the materials. The fields of materials and polymer chemistry have leveraged equilibrium concepts in an effort to mimic the structure of complex materials seen in nature. However, realizing the remarkable properties in natural systems requires moving beyond an equilibrium perspective. An alternative method to create materials with multiscale structures is to approach the issue from a kinetic perspective and utilize chemical processes to drive phase transitions.This Account features an active area of research in our group, reaction-induced phase transitions (RIPT), which use chemical reactions such as polymerizations to induce structural changes in soft material systems. Depending on the type of phase transition (e.g., microphase versus macrophase separation), the resulting change in state will occur at different length scales (e.g., nm−μm), thus dictating the structure of the material. For example, the in situ formation of either a block copolymer or a homopolymer initially in a monomer mixture during polymerization will drive nanoscale or macroscale transitions, respectively. Specifically, three different examples utilizing reaction-driven phase changes will be discussed: 1) in situ polymer grafting from block copolymers, 2) multiscale polymer nanocomposites, and 3) Lewis adduct-driven phase transitions. All three areas highlight how chemical changes via polymerizations or specific chemical binding result in phase transitions that lead to nano- and multiscale changes.Harnessing kinetic chemical processes to promote and control material structure, as opposed to organizing presynthesized molecules, polymers, or nanoparticles within a thermodynamic framework, is a growing area of interest. Trapping nonequilibrium states in polymer materials has been primarily focused from a polymer chain conformation viewpoint, in which synthesized polymers are subjected to different thermal and processing conditions. The impact of reaction kinetics and polymerization rate on final polymer material structure is starting to be recognized as a new way to access different morphologies not available through thermodynamic means. Furthermore, kinetic control of polymer material structure is not specific to polymerizations and encompasses any chemical reaction that induces morphology transitions. Kinetically driven processes to dictate material structure directly impact a broad range of areas, including separation membranes, biomolecular condensates, cell mobility, and the self-assembly of polymers and colloids. Advancing polymer material syntheses using kinetic principles such as RIPT opens new possibilities for dictating material structure and properties beyond what is currently available with traditional self-assembly techniques.