Carrageenan-modified MXene nanocomposite-based all-printed flexible humidity sensor for healthcare application

Abstract

Transition metal carbides and carbonitrides (MXene) have emerged as promising nanomaterials for humidity-sensitive applications due to their abundant hydrophilic active sites and chemically reactive surfaces. However, designing MXene-based flexible humidity sensors with rapid response rates, high sensitivity, and structural stability remains a formidable challenge. Herein, we propose an all-printed humidity sensor fabricated on a paper-based substrate with copper electrodes and carrageenan-modified MXene composite materials. The all-printed humidity sensor prepared in this work exhibited outstanding potential in humidity sensing, showcasing high sensitivity (2073.5 %) and rapid response/recovery times (4.6/5.8 s). Meanwhile, the humidity sensor exhibits outstanding structural stability (with capacitance fluctuation maintained within 8.5 % after 500 bending cycles) and remarkable cyclic stability. Based on its excellent sensing performance and stability, the CAMX-2 sensor can effectively monitor skin humidity, fingertip contact levels, and humidity changes during various exercise modes. Therefore, this work offers a viable strategy for achieving reliable humidity monitoring, showcasing significant potential in the fields of sensing devices and healthcare.