Flexible and breathable iontronic tactile sensor with personal thermal management ability for a comfortable skin-attached sensing application

Wearable sensors are tightly attached on skin of different body parts for physiological monitoring and motion detection. In addition to sensing performance and flexible formation, maintaining of the normal mass microexchange between the covered skin and external environment with appropriate thermal dissipating ability for a comfortable wearing is highly important. Herein we report the design and fabrication of a new type of flexible and breathable tactile sensor with unique personal thermal management ability. The sensor adopts a supercapacitive iontronic sensing structure with microstructures by sandwiching one porous polyurethane/ionic liquid sponge with two electrospun thermoplastic polyurethane/MXene nanofiber electrodes for an enhanced sensitivity (∼105.77 kPa−1). In addition, the intrinsic elastic nature of polymers endows the whole device with excellent mechanical flexibility and the fabric and porous internal open-ended structure of substrates provide well air and moisture permeability (∼48 mm s−1) to maintain a normal thermal dissipating ability (∼1 ℃ lower than that covered by airtight film) without causing skin redness or inflammation. Furthermore, highly solar-reflective (∼0.98) silica microparticles are incorporated into the emissive (∼0.94) thermoplastic polyurethane nanofibers to achieve an effective passive cooling effect in the outdoor scene (∼ 3 ℃ lower than that covered by fabric clothes). The developed flexible and breathable tactile sensor as well as its design and fabrication strategy provide a promising route to develop advanced wearable electronics with unique personal thermal management ability for a comfort skin-attached sensing application.