The hybrid structure of liquid metal units and organic elastomer has huge potential in achieving stretchable and reversible stiffness regulation, while such tuning is often restrained by high energy consumption for liquid metal solidification. Here, we conceive to solve the above challenge through introducing the fully leveraging interaction between supercooled liquid metal and homocrystal seeds within silicone elastomer. It is disclosed that the supercooled liquid metal-elastomer can maintain an extremely stable soft state until the supercooling is eliminated by modulating the mechanical force and elastomer deformation. This circumvents the utilization of intricate refrigeration equipment and offers a highly efficient and concise strategy for stiffness regulation. Moreover, conceptual experiments were performed to demonstrate the practical values of this technology through designing and testing the new shape memory materials, temperature-sensitive switches, and controlled circuits. The solidification mechanisms of supercooled Ga triggered by homocrystal seeds were interpreted. Overall, the present finding has generalized purposes and holds promise to significantly extend the theoretical and technological categories of classical stiffness tunable materials.
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