Li Zhaohui, Li Zewei, Zhou Shihao, Zhang Jianming, Zong Lu
Key Laboratory of Rubber-Plastics, Ministry of Education/Shandong Provincial Key Laboratory of Rubber-plastics, Qingdao University of Science & Technology, Shan Dong Sheng, Qing Dao Shi, 266042, China.
Small. 2024 Jun;20(25):e2311240. doi: 10.1002/smll.202311240. Epub 2024 Feb 1.
Shape memory hydrogels provide a worldwide scope for functional soft materials. However, most shape memory hydrogels exhibit poor mechanical properties, leading to low actuation strength, which severely limits their applications in smart biomimetic devices. Herein, a strategy for muscle-inspired shape memory-oriented polyvinyl alcohol (PVA)-natural rubber latex (NRL) hydrogel (OPNH) with multiscale oriented structure is demonstrated. The shape memory function comes from the stretch-induced crystallization of natural rubber (NR), while PVA forms strong hydrogen bonding interactions with proteins and phospholipids on the surface of NRL particles. Meanwhile, the reconfigurable interactions of PVA and NR produce a multiscale-oriented structure during stretch-drying, improving the mechanical and shape memory properties. The resultant OPNH shows excellent interfacial compatibility, exhibiting outstanding mechanical performance (3.2 MPa), high shape fixity (≈80%) and shape recovery ratio (≈92%), high actuation strength (206 kPa), working capacity (105 kJ m ), extremely short response time (≈2 s), low response temperature (28 °C) and smart thermal responsiveness. It can even maintain muscle-like working capacity when lifting a load equivalent to 372 times its weight, providing a new class shape memory material for the application in smart biomimetic muscles and multistimulus responsive devices.
形状记忆水凝胶为功能性软材料提供了广阔的应用范围。然而，大多数形状记忆水凝胶的机械性能较差，导致驱动强度较低，这严重限制了它们在智能仿生器件中的应用。在此，展示了一种制备具有多尺度取向结构的、受肌肉启发的、面向形状记忆的聚乙烯醇（PVA）-天然橡胶胶乳（NRL）水凝胶（OPNH）的策略。形状记忆功能源于天然橡胶（NR）的拉伸诱导结晶，而PVA与NRL颗粒表面的蛋白质和磷脂形成强氢键相互作用。同时，PVA和NR的可重构相互作用在拉伸干燥过程中产生多尺度取向结构，改善了机械性能和形状记忆性能。所得的OPNH表现出优异的界面相容性，具有出色的机械性能（3.2兆帕）、高形状固定率（约80%）和形状恢复率（约92%）、高驱动强度（206千帕）、工作能力（105千焦/平方米）、极短的响应时间（约2秒）、低响应温度（28℃）和智能热响应性。当举起相当于其重量372倍的负载时，它甚至能保持类似肌肉的工作能力，为智能仿生肌肉和多刺激响应器件的应用提供了一种新型形状记忆材料。
