Flexible, Breathable, and Hydrophobic Iontronic Tactile Sensors Based on a Nonwoven Fabric Platform for Permeable and Waterproof Wearable Sensing Applications

Flexible tactile sensors are under high pursuit for wearable electronics toward healthcare monitoring, human–machine interaction, and artificial intelligence. Permeability and hydrophobicity are emerging unique properties and require significant dedication of research efforts. Herein, we develop a type of flexible, breathable, and waterproof iontronic tactile sensor based on a nonwoven fabric platform using a facile dip-drying and solution-spraying technique. The intrinsic open-ended porous structure of the fabric offers air permeability (∼224.9 mm s–1), and the stearic acid microsheets decorated on the outside of the sensor provides effective hydrophobic protection (water contact angle ∼151.9°). The designed electrode-to-electrolyte interfacing microstructures of MXene microspheres and nanosheets on the fabric electrodes and the hierarchical structures with conical secondary features of chrysanthemum pollen on the fabric electrolyte endow the sensor with a high sensitivity of 214.92 kPa–1 and a wide detection range of 0–45 kPa. Fast response time, low detection limit, good dynamic response, and excellent stability are also achieved. With the help of a home-built mechatronic sensing system, the developed fabric tactile sensor can be practically used either as sensor units for human health status monitoring and motion detection or as a sensor array for spatial pressure distribution identification of human–object interaction.