【Frontiers in HaiChuan Chemical Technology】Significant progress achieved in the development of super-strong eutectic gels through mechanical training at Lanzhou Institute of Chemical Physics

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This post was last edited by Desert Fish on 2025-5-1 16:40. With the rapid development of mechanical equipment toward greater precision, larger size, automation, integration, and intelligence, there is an increasing demand for high-strength strain and pressure sensing materials that can function under extreme conditions. Recently, the Friction Physics and Sensing Team at the National Key Laboratory of Lubricant Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, proposed a \"super-hysteresis-mediated mechanical training strategy\". By integrating the orthogonal synergistic coupling of molecules and structure, they developed ultra-strong and tough eutectic gels and designed ion piezomechanical sensors that enable force-electricity conversion driven by ion flow, thus providing a new paradigm for the extreme mechanical properties of soft materials as well as for the design of force-electricity coupling mechanisms. Ultra-strong gels generally have high modulus and strength, but mechanical toughness has always been a challenge. By introducing a eutectic solvent (DES) into semi-crystalline PVA hydrogels and subjecting them to mechanical training, this study achieved a combination of ultra-high strength and excellent toughness (Figure 1). During the solvent displacement process, PVA crystallization is enhanced through hydrogen bond restructuring, resulting in dense nanocrystalline domains that confer a superhysteresis effect, thereby enabling \"superhysteresis-mediated mechanical training\" with a single pre-stretch. Meanwhile, thanks to the super-hysteresis structural blocking effect, the single-network gel after mechanical training can be further immersed in the precursor solution, and a chemically cross-linked second network is formed through free radical polymerization, resulting in hierarchical interpenetration. This hierarchical interpenetrating dual-network structure endows the gel material with micro-cooperative meso-scale multi-dimensional energy dissipation properties, thereby significantly enhancing its mechanical properties: its fracture strength reaches ~85.2 MPa, its Young’s modulus is ~98 MPa, and its fracture toughness increases to ~130.6 MJ·m−3, which are far superior to those of currently reported tough polymer gel systems (Figure 2). Motion and behavior at interfaces result in the dissipation of a large amount of mechanical energy; for example, interface friction exists, and lubrication is an effective way to reduce energy consumption. However, under some extreme operating conditions, mechanical dissipation at the interface is inevitable. To meet the demands for engineering soft materials with high load-bearing capacity or high impact resistance in such extreme environments, super-strong eutectic gels generated through mechanically induced superhysteresis can collect mechanical energy via force-to-electricity conversion, and the resulting electrical energy is used as a sensing signal to reflect pressure and strain (Figure 3). This study demonstrates the mechanical stability of eutectic gels in high-temperature environments as well as their response capability as ion piezomechanical sensors in force-to-electricity conversion driven by pressure, achieving a synergistic design that integrates strong mechanical properties with electrical properties, and providing a new design paradigm and construction strategy for the adaptive integration of performance and functionality. This research was published in Nature Communications under the title “Ultrastrong eutectogels engineered via integrated mechanical training in molecular and structural engineering”. Xu Chenggong, a doctoral student at Lanzhou Institute of Chemical Physics, is the first author of this paper; Associate Researcher Feng Yange, Researcher Wang Daai, and Academician Liu Weimin from the same institute are the co-corresponding authors. The above research was supported by projects such as the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Natural Science Foundation, and major scientific and technological projects in Gansu Province.