Wearable Electronic Devices Based On Stretchable Nanofiber Fabrics

Stretchable electronics exhibit compliant mechanical properties for intimate interactions with human body beyond conventional technologies.In a mixture of systems,Smart Textiles,which combines electronic components with everyday clothing,offer a unique advantage.A key driver for smart textiles research is the fact that both textile and electronics assembly operations are capable of fun ctionalizing large-area surfaces at very high speeds.In this article,the concept of electrical textiles is presented,along with the building blocks for its actualization.This novel category of wearable electronic systems is being contrived to converge young and innovative applications in the military,public safety,wellness care,space exploration,sports,and consumer fitness fields.This work concentrates on the realization strategy of the flexibility/stretchability of substrate materials and conductive materials,and identifies several methods for integrating conductive materials into substrate fabrics.A breathable,stretchable wearable electronic device system based on elastic nanofiber textiles was designed employing a simple and safe preparation method,which shows high electrical conductivity and stable tensile properties.The device is comfortable to wear and suitable for long-term use.The main results are summarized as follows:1.Nanofiber nonwoven fabrics based on thermoplastic elastomer were prepared by electrospinning process.The pore diameter of the fibers was in the range of 20-30 μm.There was a strong point combination between the fibers,and the surface was smooth and level,which surmounted the problem of traditional fabrics----irregularities on the surface and poor compatibility with the process.The thermoplastic polyurethane,which had good physical and mechanical properties and biocompatibility,was selected for the electrospinning method.This furnished an ideal material choice for the development of wearable electronic devices.2.The patterned silver nanowire electrode was made on the nanofiber fabrics by spraying method.The effect of the length of the silver wire on the properties of the deposited conductive network was proposed,including its micro-morphology,electrical conductivity and performance degradation under external deformation conditions.The silver nanowire was prepared by the polyol method,and two kinds of silver wires with an average length of 31.9±1.2 μm and 67.6±1.4 μm were obtained by adjusting the parameters.The electronic fiber conductor assembled by the long silver wire with a cargo of 40μg/cm2 can obtain a sheet resistance of 4Ωsq.The resistance only increased by 2.5 times after being submitted to external forces of 30%strain for 1000 times,which was far superior to the short silver wire,bringing out the synergistic assembly of the silver nanowire and the elastomer fiber.The effect provided an important scientific basis for the processing of functional electronic devices on nanofiber nonwovens.Moreover,the water/gas permeability of the conductive fiber cloth was 9.5g·h-1·m-2,which was within the range of typical skin water loss rate of the human body.3.The paper prepared a prototype machine with muscle electrical signal monitoring function,which realized the detection of physiological signals.The acquisition electrode was compared with the commercial Ag/AgCl gel electrode.The skin/electrode contact resistance of the device was slightly higher.The collected signals showed significant muscle contraction characteristics with a signal-to-noise ratio of 17.1 dB.After 12 hours of long-term wear,the skin below the gel electrode showed swelling,while that under the dry silver nanowire electrodes showed no obvious reaction and yet kept a high degree of signal acquisition ability.By entering and analyzing the multi-channel electromyogram signals,using Python’s built-in XGboost module for learning and grooming,the wrist motion was accurately identified,demonstrating the potential of the device in the field of wearable technology.