Control nucleation for strong and tough crystalline hydrogels with high water content
Limei Huang, Hao Li, Shunxi Wen, Penghui Xia, Fanzhan Zeng, Chaoyi Peng, Jun Yang, Yun Tan, Ji Liu, Lei Jiang, Jianfeng Wang
Abstract
Hydrogels, provided that they integrate strength and toughness at desired high content of water, promise in load-bearing tissues such as articular cartilage, ligaments, tendons. Many developed strategies impart hydrogels with some mechanical properties akin to natural tissues, but compromise water content. Herein, a strategy deprotonation-complexation-reprotonation is proposed to prepare polyvinyl alcohol hydrogels with water content as high as ~80% and favorable mechanical properties, including tensile strength of 7.4 MPa, elongation of around 1350%, and fracture toughness of 12.4 kJ m−2. The key to water holding yet improved mechanical properties lies in controllable nucleation for refinement of crystalline morphology. With nearly constant water content, mechanical properties of as-prepared hydrogels are successfully tailored by tuning crystal nuclei density via deprotonation degree and their distribution uniformity via complexation temperature. This work provides a nucleation concept to design robust hydrogels with desired water content, holding implications for practical application in tissue engineering. Tough hydrogels are desirable but balancing material properties and water content is challenging. Here, the authors report the development of a material with favorable properties and high water content by a nucleation strategy.