College of Naval Architecture and Ocean Engineering, Naval University of Engineering, Wuhan 430022, China.
Staff Room of Chemistry and Material, Department of Basic Course, Naval University of Engineering, Wuhan 430022, China.
ACS Appl Mater Interfaces. 2023 May 31;15(21):26016-26027. doi: 10.1021/acsami.3c03880. Epub 2023 May 18.
Stiffness variable polymers are an essential family of materials that have aroused considerable attention in soft actuators. Although lots of strategies have been proposed to achieve variable stiffness, it remains a formidable challenge to achieve a polymer with a wide stiffness range and fast stiffness change. Herein, a series of variable stiffness polymers with a fast stiffness change and wide stiffness range were successfully synthesized, and the formulas were optimized via Pearson correlation tests. The rigid/soft stiffness ratio of the designed polymer samples can reach up to 1376-folds. Impressively, owing to the phase-changing side chains, the narrow endothermic peak can be observed with full width at half-maximum within 5 °C. Moreover, the shape memory properties of the shape fixity () and shape recovery ratio () values of the shape memory properties could reach up to 99.3 and 99.2%, respectively. Then, the obtained polymer was introduced into a kind of designed 3D printing soft actuator. The soft actuator can achieve sharp heating-cooling cycle of 19 s under a 1.2 A current with 4 °C water as coolant and can lift a 200 g weight at the actuating state. Moreover, the stiffness of the soft actuator can reach up to 718 mN/mm. The soft actuator exhibits an outstanding actuate behavior and stiffness switchable capability. We expect our design strategy and obtained variable stiffness polymers to be potentially applied in soft actuators and other devices.
刚性-可变形聚合物是一类重要的材料，在软驱动器中引起了相当大的关注。尽管已经提出了许多策略来实现可变刚度，但要实现具有宽刚度范围和快速刚度变化的聚合物仍然是一个巨大的挑战。在此，成功合成了一系列具有快速刚度变化和宽刚度范围的可变刚度聚合物，并通过 Pearson 相关测试优化了公式。设计的聚合物样品的刚性/可变形刚度比可达 1376 倍。令人印象深刻的是，由于相变化侧链，可以在 5°C 内观察到全宽半最大值的狭窄吸热峰。此外，形状记忆性能的形状固定（）和形状恢复比（）值可分别达到 99.3%和 99.2%。然后，将得到的聚合物引入到一种设计的 3D 打印软驱动器中。软驱动器可以在 1.2 A 电流下使用 4°C 的水作为冷却剂实现 19 s 的急剧加热-冷却循环，并在驱动状态下提升 200 g 的重量。此外，软驱动器的刚度可达 718 mN/mm。软驱动器表现出出色的驱动行为和可切换的刚度。我们期望我们的设计策略和获得的可变刚度聚合物有望应用于软驱动器和其他设备。
