Wu Jia, Wu Baohu, Xiong Jiaqing, Sun Shengtong, Wu Peiyi
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry, Chemical Engineering and Biotechnology & Center for Advanced Low-dimension Materials, Donghua University, Shanghai, 201620, China.
Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ) Forschungszentrum Jülich, Lichtenbergstr. 1, 85748, Garching, Germany.
Angew Chem Int Ed Engl. 2022 Aug 22;61(34):e202204960. doi: 10.1002/anie.202204960. Epub 2022 Jul 11.
Thermal stiffening materials that are naturally soft but adaptively self-strengthen upon heat are intriguing for load-bearing and self-protection applications at elevated temperatures. However, to simultaneously achieve high modulus change amplitude and high mechanical strength at the stiffened state remains challenging. Herein, entropy-mediated polymer-mineral cluster interactions are exploited to afford thermal stiffening hydrogels with a record-high storage modulus enhancement of 13 000 times covering a super wide regime from 1.3 kPa to 17 MPa. Such a dramatic thermal stiffening effect is ascribed to the transition from liquid-liquid to solid-liquid phase separations, and at the molecular level, driven by enhanced polymer-cluster interactions. The hydrogel is further processed into sheath-core fibers and smart fabrics, which demonstrate self-strengthening and self-powered sensing properties by co-weaving another liquid metal fiber as both the joule heater and triboelectric layer.
热硬化材料通常质地柔软，但在受热时会自适应地自我强化，这对于高温下的承重和自我保护应用来说很有吸引力。然而，要在硬化状态下同时实现高模量变化幅度和高机械强度仍然具有挑战性。在此，利用熵介导的聚合物 - 矿物簇相互作用来制备热硬化水凝胶，其储能模量提高了13000倍，创历史新高，涵盖了从1.3 kPa到17 MPa的超宽范围。这种显著的热硬化效应归因于从液 - 液到固 - 液的相分离转变，在分子水平上，是由增强的聚合物 - 簇相互作用驱动的。该水凝胶进一步加工成皮芯纤维和智能织物，通过将另一种液态金属纤维同时作为焦耳加热器和摩擦电层进行共编织，展现出自我强化和自供电传感特性。
