Huang Zhangjun, Jia Haiyan, Muyden Antoine P van, Fei Zhaofu, Dyson Paul J
Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland.
ACS Appl Mater Interfaces. 2019 Aug 28;11(34):31311-31316. doi: 10.1021/acsami.9b09426. Epub 2019 Aug 1.
Natural polymers such as those present in foods contain abundant noncovalent intra- and intermolecular interactions, notably hydrogen bonds, which make them rigid when dry, but on exposure to water soften, due to disruption of these interactions. This softening process allows them to be reshaped. Food-derived materials, however, have limited practical use due to their high brittleness and gradual degradation. Nevertheless, inspired by such properties, surfactant-polyelectrolyte-based polymers that contain abundant ionic interactions and can be repeatedly reshaped using water as plasticizer are described. The polymers, on the basis of main chain anionic poly(styrene sulfonates) combined with phosphonium surfactant, are readily synthesized with well-defined lamellar domains through interfacial metathesis reactions. The polymers present typical stress-strain characteristics of plastics, and their modulus undergoes a decrease of ca. 3 orders of magnitude upon shear and stretch forces after plasticizing with water. Since recycling of plastics generally involves complicated and energy-intensive processes (that leads to the majority of plastics being land-filled or incinerated), it is envisaged that reshapable polymers, such as those described here, could reduce the amount of plastic waste as they can be remolded as and when required, thus reducing pollution and the depletion of resources, ultimately contributing to a more sustainable society.
天然聚合物，如食品中存在的那些聚合物，含有丰富的非共价分子内和分子间相互作用，尤其是氢键，这使得它们在干燥时变硬，但在接触水时会变软，这是由于这些相互作用被破坏所致。这种软化过程使它们能够被重塑。然而，食品衍生材料由于其高脆性和逐渐降解而实际用途有限。尽管如此，受这些特性的启发，本文描述了基于表面活性剂 - 聚电解质的聚合物，它们含有丰富的离子相互作用，并且可以使用水作为增塑剂进行反复重塑。这些聚合物以主链阴离子型聚（苯乙烯磺酸盐）与鏻表面活性剂结合为基础，通过界面复分解反应很容易合成出具有明确层状结构域的聚合物。这些聚合物呈现出典型的塑料应力 - 应变特性，并且在用水处理增塑后，它们的模量在剪切和拉伸力作用下会降低约3个数量级。由于塑料的回收通常涉及复杂且耗能的过程（这导致大多数塑料被填埋或焚烧），可以设想，本文所述的可重塑聚合物能够减少塑料废物的数量，因为它们可以根据需要随时重塑，从而减少污染和资源消耗，最终为更可持续的社会做出贡献。
