A waterproof,environment-friendly,multifunctional,and stretchable thermoelectric fabric for continuous self-powered personal health signal collection at high humidity

Thermoelectric sensors have attracted increasing attention in smart wearables due to the recognition of multiple signals in self-powered mode.However,present thermoelectric devices show disadvantages of low durability,weak wearability,and complex preparation processes and are susceptible to moisture in the microenvironment of the human body,which hinders their further application in wearable electronics.Herein,we prepared a new thermoelectric fabric with thermoplastic polyurethane/carbon nanotubes(TPU/CNTs)by combining vacuum filtration and electrospraying techniques.Electrospraying TPU microsphere coating with good biocompatibility and environmental friendliness made the fabric worn directly and exhibits preferred water resistance,mechanical durability,and stability even after being bent 4000 times,stretched 1000 times,and washed 1000 times.Moreover,this fabric showed a Seebeck coefficient of 49μVK−1 and strain range of 250%and could collect signals well and avoided interference from moisture.Based on the biocompatibility and safety of the fabric,it can be fabricated into devices and mounted on the human face and elbow for long-term and continuous collection of data on the body’s motion and breathing simultaneously to provide collaborative support information.This thermoelectric fabric-based sensor will show great potential in advanced smart wearables for health monitoring,motion detection,and human–computer interaction.

多功能热电织物用于可穿戴无线传感系统

Flexible thermoelectric materials play an important role in smart wearables,such as wearable power generation,self-powered sensing,and personal thermal management.However,with the rapid development of Internet of Things(IoT)and artificial intelligence(AI),higher standards for comfort,multifunctionality,and sustainable operation of wearable electronics have been proposed,and it remains challenging to meet all the requirements of currently reported thermoelectric devices.Herein,we present a multifunctional,wearable,and wireless sensing system based on a thermoelectric knitted fabric with over 600 mm·s^(-1)air permeability and a stretchability of 120%.The device coupled with a wireless transmission system realizes self-powered monitoring of human respiration through an mobile phone application(APP).Furthermore,an integrated thermoelectric system was designed to combine photothermal conversion and passive radiative cooling,enabling the characteristics of being powered by solar-driven in-plane temperature differences and monitoring outdoor sunlight intensity through the APP.Additionally,we decoupled the complex signals of resistance and thermal voltage during deformation under solar irradiation based on the anisotropy of the knitted fabrics to enable the device to monitor and optimize the outdoor physical activity of the athlete via the APP.This novel thermoelectric fabricbased wearable and wireless sensing platform has promising applications in next-generation smart textiles.

Design and Fabrication of Flexible Thermoelectric String-Based Fabrics

Flexible thermoelectric(TE)materials that convert heat into electricity have been widely used in wearable electronics and other flexible devices.In this work,inorganic TE pillars were combined with thermoplastic polyurethane(TPU)to assemble a flexible string-shaped TE generator(TEG)for the fabrication of the thermoelectric fabric(TEF).Moreover,finite element analysis(FEA)was used to optimize the dimensions of the TE string and evaluate its performance.The FEA results showed that the inter-pillar spacing significantly affected the temperature difference,the output voltage and the internal resistance.A maximum power density of 3.43μW/cm^(2)(temperate gradientΔT=10.5 K)was achieved by the TE string with a diameter of 3.5 mm and an inter-pillar spacing of 2 mm.However,under the experimental condition,the achievable power density of the fabricated three-dimensional(3D)TEF was limited to 29%of the simulation result because of the inclination of the TE string within the fabric concerning heat plate contact and copper wire-TE pillar connections.The actual TE string also demonstrated high flexibility and stable mechanical properties after 450 bending cycles.Thus,the study would provide a foundation for future research in developing more efficient TEFs to offer a comfortable and conformable option for wearable energy harvesting applications.

All‑Fiber Integrated Thermoelectrically Powered Physiological Monitoring Biosensor

Advanced fabric electronics for long-term personal physiological monitoring,with a self-sufficient energy source,high integrity,sensitivity,wearing comfort,and homogeneous components are urgently desired.Instead of assembling a self-powered biosensor,comprising a variety of materials with different levels of hardness,and supplementing with a booster or energy storage device,herein,an all-fiber integrated thermoelectrically powered physiological monitoring device(FPMD),is proposed and evaluated for production at an industrial scale.For the first time,an organic electrochemical transistor(OECT)biosensor is enabled by thermoelectric fabrics(TEFs)adaptively,sustainably and steadily without any additional accessories.Moreover,both the OECT and TEFs are constructed using a cotton/poly(3,4-ethylenedioxythiophene):poly(styrenesulfon ate)/dimethylsulfoxide/(3-glycidyloxypropyl)trimethoxysilane(PDG)yarn,which is lightweight,robust(90°bending for 1000 cycles)and sweat-resistant(ΔR/R0=1.9%).A small temperature gradient(ΔT=2.2 K)between the environment and the human body can drive the high-gain OECT(71.08 mS)with high fidelity,and a good signal to noise ratio.For practical applications,the on-body FPMD produced an enduring and steady output signal and demonstrated a linear monitoring region(sensitivity of 30.4 NCR(normalized current response)/dec,10 nM~50µM)for glucose in artificial sweat with reliable performance regarding anti-interference and reproducibility.This device can be expanded to the monitoring of various bio-markers and provides a new strategy for constructing wearable,comfortable,highly integrated and self-powered biosensors.