The self-assembly of dialdehyde-cellulose-nanofiber-based hydrogels with high compression resilience

Abstract Cellulose-nanofiber-based hydrogels (CNF-Gel) exhibit excellent mechanical properties and designable functions. However, it is difficult to coordinate the complex self-assembly structure and various functions, which limits the widespread use of CNF-Gel. Here, a simple and environmental-friendly approach for the preparation of three-dimensional dialdehyde-cellulose-nanofiber-based hydrogels (DAC-Gel) was developed via periodate oxidation of cellulose-nanofiber and freeze drying. The self-assembled DAC-Gel with flexible skeleton structure and numerous aldehyde groups was synthesized without organic solvents or cross-linking agents added. After 100 compression-releasing cycles at a maximum compressive strain of 30%, DAC-Gel-1.5 remained high stress remaining and low energy loss coefficient, demonstrating durable compressive property. As the functional intermediate, DAC-Gel can be further modified to conveniently prepare functional products, which shows a variety of potential applications such as in the carbon capture and storage. After amination with polyethylenimine via Schiff base reaction, the DAC-based CO 2 adsorbent DAC-1.5@PEI still remained good elasticity. The introduction of PEI endowed DAC-1.5@PEI with high nitrogen content (18.57 wt%) and CO 2 adsorption capacity (2.63 mmol/g) under humid condition. This research develops a synthesis method of flexible and three-dimensional cellulose-based materials from another perspective, and provides useful information for understanding the synthesis process of DAC-Gel in different sizes. Graphical abstract