Sun Xia, Mao Yimin, Yu Zhengyang, Yang Pu, Jiang Feng
Sustainable Functional Biomaterials Laboratory, Bioproducts Institute, Department of Wood Science, Faculty of Forestry, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Department of Materials Science and Engineering, University of Maryland, College Park, Maryland, MD, 20742, USA.
Adv Mater. 2024 Jun;36(25):e2400084. doi: 10.1002/adma.202400084. Epub 2024 Mar 27.
Recently, hydrogel-based soft materials have demonstrated huge potential in soft robotics, flexible electronics as well as artificial skins. Although various methods are developed to prepare tough and strong hydrogels, it is still challenging to simultaneously enhance the strength and toughness of hydrogels, especially for protein-based hydrogels. Herein, a biomimetic "salting out-alignment-locking" tactic (SALT) is introduced for enhancing mechanical properties through the synergy of alignment and the salting out effect. As a typical example, tensile strength and modulus of initially brittle gelatin hydrogels increase 940 folds to 10.12 ± 0.50 MPa and 2830 folds to 34.26 ± 3.94 MPa, respectively, and the toughness increases up to 1785 folds to 14.28 ± 3.13 MJ m. The obtained strength and toughness hold records for the previously reported gelatin-based hydrogel and are close to the tendons. It is further elucidated that the salting out effect engenders hydrophobic domains, while prestretching facilitates chain alignment, both synergistically contributing to the outstanding mechanical properties. It is noteworthy that the SALT demonstrates remarkable versatility across different salt types and polymer systems, thus opening up new avenues for engineering strong, tough, and stiff hydrogels.
最近，水凝胶基软材料在软体机器人、柔性电子以及人造皮肤领域展现出了巨大潜力。尽管已开发出多种方法来制备坚韧的水凝胶，但要同时提高水凝胶的强度和韧性仍具有挑战性，尤其是对于蛋白质基水凝胶而言。在此，引入了一种仿生的“盐析 - 排列 - 锁定”策略（SALT），通过排列作用和盐析效应的协同作用来增强机械性能。作为一个典型例子，初始脆性的明胶水凝胶的拉伸强度和模量分别提高了940倍至10.12±0.50 MPa和2830倍至34.26±3.94 MPa，韧性提高至1785倍至14.28±3.13 MJ m。所获得的强度和韧性在先前报道的明胶水凝胶中保持着记录，并且接近肌腱的性能。进一步阐明的是，盐析效应产生疏水区域，而预拉伸促进链排列，两者协同作用导致了出色的机械性能。值得注意的是，SALT在不同的盐类型和聚合物体系中都表现出显著的通用性，从而为设计强韧且坚硬的水凝胶开辟了新途径。
