Fabrication And Application Of Highly Conductivive,Stretchable,and Breathable Electrodes Based On Polyurethane Fibers

Stretchable electrodes,as an indispensable component in wearable electronics,have been one of the frontier research hotspots in the field of flexible electronics and sensing.However,due to its unique application scenarios,short development time,and immature fabricating technology,most of the current stretchable electrode structures or materials have low conductivity retention under high strain,poor stability and durability,lack of breathability and complex fabrication process.In this paper,a stretchable electrode fabricating process based on ultrasonic cavitation treatment was proposed.The fibrous polyurethane mat was fabricated through a facile electrospinning technique.The carbon nanotubes（CNTs）were driven to be embedded and interlocked with each other onto electrospun polyurethane mat（EPUM）by the ultrasonic cavitation treatment,forming a highly stable and reliable conductive network.The key properties of the prepared EPUM/CNTs stretchable electrode,such as electromechanical and thermal behaviors,stability,permeability and moisture permeability,were tested and analyzed,and the application research was carried out in the fields of wearable energy storage devices and strain sensors.1.Based on the Rayleigh-Plesset bubble dynamics equation,the difference of transient cavitation and stable cavitation were analyzed,as well,the effects of driving sound pressure amplitude,surface tension,hydrostatic pressure,initial bubble radius on ultrasonic cavitation were clarified.The load mechanism of ultrasonic cavitation was clarified to provide theoretical support for the realization of carbon nanotubes being embedded onto EPUM.2.Ultrasonic cavitation experimental platform was constructed,and the influences of the length of CNTs,configuration method of reaction solution,ultrasonic time,and ultrasonic power on the morphology and conductivity of EPUM/CNTs were investigated.Also,the elements,structures,mechanical properties,electrical conductivity,cyclicity,wearability of the EPUM/CNTs mat were characterized and tested.The results showed that EPUM/CNTs stretchable electrodes had good stretchability（recoverable stretching rate up to 200%）,high conductivity(sheet resistance of 32.1Ω·sq^-1),excellent stability（over 50,000 stretching cycles）,efficient air permeability(22.83 mm·s^-1 at pressure difference of 100 Pa)and moisture-penetrability(0.22 g·cm^-2·h^-1).3.Based on EPUM/CNTs stretchable electrodes,the application researches were developed in wearable energy storage and strain sensing.The electrochemical deposition processes of transition metal oxide MnO₂,layered double hydroxide CoNi-LDH and conductive polymer PANI on EPUM/CNTs films were investigated.Then,all-solid EPUM/CNTs@PANI supercapacitors were assembled and successfully driven electronic components.Wearable strain sensor was fabricated with EPUM/CNTs mat,the detection range,sensitivity,hysteresis,response time and cycling performance of the sensor were tested and analyzed.Furthermore,it was applied to a wearable strain sensor to detect the bending signal of manipulator fingers,realizing human gestures recognition.