Jingchun Lv

In wearable electronic devices, designing flexible pressure sensors with high sensitivity, excellent mechanical stability, outstanding bending performance, and good electrical and response stability remains a significant challenge. Selecting an appropriate structure and materials with high electrical conductivity is crucial to addressing this challenge. This study synthesizes PANI nanowires using interfacial polymerization and fabricates a novel wrinkled microstructure through repetitive stretching. A flexible pressure sensor based on wrinkled PANI nanowire films was successfully constructed. This sensor exhibits not only excellent electrical and response stability but also high sensitivity, with sensitivity values of 22.23 kPa ^-1 (5 Pa to 3 kPa), 7.89 kPa ^-1 (3 kPa to 18 kPa), and 3.32 kPa ^-1 (18 kPa to 36 kPa). The response times are 97 ms and 128 ms, respectively, with outstanding mechanical stability and bending performance. Thus, the pressure sensor developed in this work has potential application value in high-sensitivity tactile perception, human-computer interfaces, and weak signal detection.

With the development of wearable electronic devices, there has been extensive research interest in portable energy supply systems. In this study, traditional cotton fabrics are finished with a water repellent coating and a single‐sided polyurethane (PU) coating to impart hydrophobicity. The hydrophobic lightweight cotton fabric can float on the surface of the pyrrole polymerization system solution. With increasing polymerization time, the pyrrole continues to polymerize and deposit on the side in contact with the fabric, resulting in a one‐sided conductive fabric. The highest doping level was obtained for the polypyrrole (PPy) coating for polymerization time of 12 h. For PPy coating thickness of 18 μm, the square resistance was as low as 220 Ω/sq. The PPy‐12 fabric electrode showed excellent electrochemical performance and cycling stability. An interdigitated pattern was etched on the surface of the one‐sided conductive fabric (PPy‐12) using a N, N‐dimethylformamide solution. Fabric micro‐supercapacitors were obtained by assembling with a H₂SO₄/PVA gel electrolyte. The fabric micro‐supercapacitor exhibited good flexibility and electrochemical energy storage properties. For current density of 0.08 mA/cm² and power density of 19.1 μW/cm², the energy density of the device was 0.09 μWh/cm². After 3000 cycles, the micro‐supercapacitor retained approximately 85% of the capacitance. Thus, fabric‐based flexible micro‐supercapacitors have excellent application potential in the field of energy storage.

Textile-based electronics hold great promise as they can endow wearable devices with soft and comfortable characteristics. In this work, a multifunctional conductive yarn was fabricated by coating a commercial regenerated cellulose (lyocell) yarn with polypyrrole (PPy). The method is simple, low-cost, and highly scalable and it endows the common lyocell yarn with flame-retardant as well as good electrical heating properties and excellent electrochemical performance. The PPy-coated lyocell yarn (PCLY) behaved as a regular yarn and could be hand-knitted into a full fabric. The PCLY fabric demonstrated high conductivity, allowing its use as a wearable Joule heater. The polypyrrole coating significantly improved the limiting oxygen index (LOI) of the lyocell yarn from 21.7% to 40.2%, endowing the yarn with an excellent flame-retardant property. PCLY was stitched into a fabric to form interdigitated electrodes and further assembled into flexible textile micro-supercapacitors. The resulting device with 10 interdigitated electrodes exhibited high areal specific capacitance of 663 mF cm⁻² and energy density of 21.6 μW h cm⁻² at 1 mA cm⁻². Furthermore, six devices in series could power a blue light-emitting-diode (LED) of 3 V for more than 30 seconds. This facile fabrication provides novel and practical insights toward wearable textile-based electronics.