A Universal Strategy to Mitigate Microphase Separation via Cellulose Nanocrystal Hydration in Fabricating Strong, Tough, and Fatigue-Resistant Hydrogels————————————————————

發(fā)表狀態(tài)：

AM. 2024.

研究團隊：

Jiang Fang等人

研究內(nèi)容：

本研究創(chuàng)新性地提出了一種通用的相工程策略，利用纖維素納米晶（CNC）調(diào)控乙酸鈉（NaAc）結(jié)晶誘導(dǎo)的微相分離，成功制備出兼具高強度、高韌性、高延展性和抗疲勞性的纖維素復(fù)合水凝膠。研究發(fā)現(xiàn)，單獨添加NaAc會因NaAc·3H2O晶體的形成引發(fā)嚴重的微相分離，從而制得剛性且缺乏彈性的水凝膠。而通過引入CNC，其獨特的水合效應(yīng)能夠競爭性結(jié)合晶體中的水分子，有效緩解微相分離，成功實現(xiàn)了剛性水凝膠向彈性、強韌且耐疲勞水凝膠的轉(zhuǎn)變。這一研究不僅深化了纖維素在調(diào)控軟材料結(jié)構(gòu)與性能中的核心作用，同時也為未來高性能水凝膠的設(shè)計提供了新思路和新方法。

Abstract：

As a common natural phenomenon, phase separation is exploited for the development of high-performance hydrogels. Using supersaturated salt to create microphase-separated hydrogels with strengthened mechanical properties has gained widespread attention. However, such strengthened hydrogel loses its intrinsic flexibility, making the phase separation strategy unsuitable for the fabrication of stretchable and tough hydrogels. Here, a phase-engineering design strategy is introduced to produce stretchable yet tough hydrogels using supersaturated NaAc salt, by leveraging the hydration effect of cellulose nanocrystal (CNC) to mitigate microphase separation. The CNC-mitigated microphase-separated hydrogel presents unprecedented mechanical properties, for example, tensile strength of 1.8 MPa with a fracture strain of 4730%, toughness of 43.1 MJ m?3, fracture energy of 75.4 kJ m?2, and fatigue threshold up to 3884.7 J m?2. Furthermore, this approach is universal in synthesizing various microphase separation-enhanced polymer gels, including polyacrylic acid, poly(acrylic acid-co-acrylamide), gelatin, and alginate. These advancements provide insights into the incorporation of CNC-mediated microphase separation structures in hydrogels, which will foster the future development of high-performance soft materials.