Biomimetic multilayer flexible sensors for multifunctional underwater sensing

The development of multifunctional flexible sensors capable of monitoring different physiological signals of the body underwater holds great practical significance in safeguarding the well-being of divers during their subaquatic activities. Here, we prepared a multilayer multifunctional sensor that mimics the structure of human skin by sequentially constructing a sensing layer formed by multi -walled carbon nanotubes and a hydrophobic protective layer formed by organosilicon dioxide (o-SiO 2 ) on the elastomer surface. The o-SiO 2 layer is superhydrophobic and breathable, also allowing the sensing layer to be only partially wetted. The sensor can monitor human respiration by sensing humidity due to breathability of protective layer. Additionally, the superhydrophobic surface ensures stable strain monitoring even underwater. The partially wetted sensing layer allows the sensor to respond to its immersion and surfacing processes, as well as underwater bubbles. These multifunctional sensors are capable of real-time monitoring of divers' physiological signals, including breathing patterns and motions, throughout underwater activities.