Interlayer cross-linked MXene enables ultra-stable printed paper-based flexible sensor for real-time humidity monitoring

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-09, Vol.495, p.153343, Article 153343
• Main Authors: Zhang, Hao-wen, Xu, Xiang, Huang, Meng-lin, Wang, Yang-sheng, Xu, Zhao-quan, Feng, Zhe-sheng, Zhang, Yagang, Wang, Yan
• Format: Article
• Language: English
• Subjects: Humidity sensor; MXene; Polyethyleneimine; Silver nitrate; Stability
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.153343

This research successfully synthesized a cross-linking modified MXene composite material, which could be used in preparation of the paper-based humidity sensor to endow it with structural stability, antioxidant property, and efficient real-time humidity monitoring performance. [Display omitted] •The PMX6-A7 was prepared by the PEI/AgNO3 cross-linking modifying MXene.•The flexible humidity sensor presented excellent moisture sensitivity and stability.•The assembled monitor possessed effective real-time humidity monitoring performance.•The ECP technology endowed this research potential for large-scale application. With an abundance of hydrophilic active sites present on the surfaces, MXene exhibits significant potential for application in the field of humidity monitoring. Nevertheless, achieving the high response intensity, excellent response sensitivity, structural stability, and oxidation resistance in the MXene-based humidity sensors remains a formidable challenge. Herein, we propose a humidity sensor made from the paper-based flexible sensor with copper electrode and polyethyleneimine/silver nitrate cross-linking modified MXene composite materials. The humidity sensor prepared in this work presents a satisfactory capacitance response rate (819.9 % in 97 % RH) and favorable sensitivity (6.9/11.9 s for response/recovery time). Meanwhile, the humidity sensor possesses outstanding structural stability (less than 3 % attenuation of the capacitance response after 100 bending cycles) and superior oxidation resistance. Moreover, the real-time humidity monitor assembled based on the humidity sensor has realized the effective monitoring of human skin humidity and dynamic respiration. Consequently, this study provides a viable approach for achieving reliable real-time humidity monitoring, demonstrating significant potential in the realms of intelligent actuators, sensing devices, and health care.