Recently, Professor Peng Feng's research group from the College of Materials Science and Technology has made new progress in the field of hemicellulose /MXene composite gel materials. The research result "Long-term stable and catalytic 2D MXene nanosheets wrapped with dialdehyde xylan for ultrafast gelation" was published in the international journal Green Chemistry (IF=11.034).

MXenes (Ti3C2Tx) are emerging 2D layered transition metal carbide/nitride materials due to their excellent electronic, optical, and mechanical properties. Abundant hydrophilic groups such as –OH, –O, and –F enhanced their hydrophilicity to a great extent, making them excellent conductive hydrogel fillers. MXene nanosheets always undergo rapid degradation when exposed to water and oxygen, and the incorporation of reducing or capping agents may deteriorate the intrinsic characteristics of MXenes. As a result, developing aqueous stable and catalytic Ti3C2Tx MXene suspensions remains a grand challenge.

In this work, the research team coupled dialdehyde xylan (DAX) with MXene nanosheets to significantly increase the long-term storage of MXene in an aqueous solution (>3 months) with a dramatic enhancement of their room temperature catalytic activity for ultrafast gelation. This work offers an enticing prospect for the development of eco-friendly and high-performance MXene-based materials.

Schematic illustration of stable, sustainable, and catalytic DAX/MXene nanosheets

and their application for ultrafast gelation

The results prove that DAX can form thick and smooth layers on the nanosheets via multiple hydrogen bonds, providing a reduction environment to prevent the occurrence of oxidation. Meanwhile, DAX can accelerate the generation of free radicals from the potassium persulfate (KPS)/MXene pair, reducing the polymerization time of vinyl monomers from ∼30 min to ∼90 s. Moreover, the DAX layer is capable of serving as additional crosslinks by leveraging Schiff base bonds with chitosan (CS), with the elongation at break increasing from 100% to 909%. The resultant MXene-based hydrogel can be further explored as a sustainable sensor for real-time physical signal monitoring.

The first author of this paper is Li Nan, a doctoral candidate from the College of Materials Science and Technology, and the corresponding authors are professor Peng Feng and associate professor Hao Xiang. The College of Materials Science and Technology is the unit of the first signature. This research was funded by the National Natural Science Foundation of China (31971611), the Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education of China (KF202007), the National Science Fund for Distinguished Young Scholars of China (32225034), National Key Research and Development Project of China (2022YFB4201904), and the Ministry of Education, China-111 Project (BP0820033).

Paper Link: https://pubs.rsc.org/en/content/articlelanding/2023/gc/d3gc00363a