Department of Chemistry, The University of Sheffield, Sheffield, S3 7HF, UK.
Croda International Plc, Snaith, Goole, DN14 9AA, UK.
Nat Commun. 2020 Jul 6;11(1):3372. doi: 10.1038/s41467-020-17167-8.
Synthetic polymers are thoroughly embedded in the modern society and their consumption grows annually. Efficient routes to their production and processing have never been more important. In this respect, silk protein fibrillation is superior to conventional polymer processing, not only by achieving outstanding physical properties of materials, such as high tensile strength and toughness, but also improved process energy efficiency. Natural silk solidifies in response to flow of the liquid using conformation-dependent intermolecular interactions to desolvate (denature) protein chains. This mechanism is reproduced here by an aqueous poly(ethylene oxide) (PEO) solution, which solidifies at ambient conditions when subjected to flow. The transition requires that an energy threshold is exceeded by the flow conditions, which disrupts a protective hydration shell around polymer molecules, releasing them from a metastable state into the thermodynamically favoured crystalline state. This mechanism requires vastly lower energy inputs and demonstrates an alternative route for polymer processing.
合成聚合物已被广泛应用于现代社会，其消耗量逐年增加。高效的生产和加工途径从未如此重要。在这方面，丝蛋白的原纤化优于传统的聚合物加工，不仅能获得高强度和高韧性等优异的材料物理性能，而且还提高了工艺能源效率。天然丝在液体流动时通过构象依赖的分子间相互作用凝固，从而使蛋白质链去溶剂化（变性）。在这里，通过水溶液中的聚（氧化乙烯）（PEO）溶液复制了这一机制，当溶液受到流动时，它会在环境条件下凝固。这种转变要求流动条件超过能量阈值，从而破坏聚合物分子周围的保护性水合壳，使它们从亚稳态进入热力学有利的结晶态。这种机制需要的能量输入要低得多，并为聚合物加工提供了一种替代途径。
