Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> Aerogel-Based Wearable\nHumidity Sensors with Low Hysteresis\nand High Linearity for Expiratory Comfort Management

Wearable and flexible humidity sensors hold great promise\nfor expiratory\ncomfort management. However, the high hysteresis and poor detection\nlinearity restrict the immediate and accurate detection of humidity.\nHerein, we have prepared Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene/chitosan/polyvinylidene difluoride aerogels\nwith a controllable hydrophobic/hydrophilic surface to regulate the\ncatch/escape behavior of H<sub>2</sub>O molecules. The MXene aerogel-based\nhumidity sensor demonstrates low hysteresis (3.2% relative humidity)\nand a high linear relationship (<i>R</i><sup>2</sup> = 0.99).\nIntegrated with a control circuit, an expiratory humidity monitoring\nsystem is constructed for nasal comfort management as a humidity switch.\nThe exhaled breath humidity can be automatically regulated during\ndry exhalation conditions. This wearable humidity sensor enables the\nreal-time monitoring and intelligent control of nasal exhaled humidity.\nThis work represents a new avenue for improving breathing comfort\nand preventing respiratory diseases.