Fabrication and Characterization of Yarn-Based Temperature Sensor for Respiratory Monitoring

The development of wearable technologies promotes the research of flexible sensors.It is hoped that a flexible sensor can collect different physiological data,such as temperature and respiratory rate(RR).The temperature of the exhaled gas is generally higher than that in the air,and the periodic change of temperature is related to the respiratory rate.In this work,we use platinum fiber and spandex fiber to prepare yarn-based temperature sensor with high tensile performance through hollow spindle wrapping spinning technology.After the measurement,the sensitivity of the sensor can reach at least 3.18×10^(-3)℃^(-1).We use the sensor and ordinary fabric mask to prepare a sensor mask that can monitor human respiratory signals to explore the performance of the sensor in RR measurement.The experimental results show that when measuring human RR,the yarn-based temperature sensor can accurately distinguish different respiratory states such as normal breathing,deep breathing,and rapid breathing while speaking.It is suggested that yarn-based temperature sensors can be used in medical fields such as real-time respiratory detection and temperature measurement.

High-efficiency preparation of multifunctional conjugated electrospun graphene doped PVDF/CF yarns for energy harvesting and human movement monitoring in TENG textile

Portable power is an effective solution to realize self-powered sensors for wearable devices,promoting future sustainable development.Membrane-based triboelectric nanogenerators(M-TENGs)have emerged as a promising technology for harvesting biomechanical energy from human motion owing to their advantages,such as simple structure,lightweight design,and efficient energy conversion.However,the poor durability,low adaptability,and un-washability of two-dimensional membrane materials have largely hindered their application in wearable electronics.In this study,we propose a sheath-core polyvinylidene fluoride(PVDF)/graphene(G)-carbon fiber(CF)yarn fabricated via conjugate electrospinning,comprising a commercial CF core and an electrospun graphene-doped PVDF sheath,which improves the fatigue resistance of electrospun nanofiber films under prolonged friction and keeps a high degree of freedom.The resulting electronic textile,woven with the large-scale electrospun PVDF/G-CF yarn,demonstrates a remarkable power density of 25.5 mW·m^(-2).The tight distribution of PVDF/G nanofibers on the textile surface ensures excellent softness,washability,and durability.Furthermore,the electrospun PVDF/G-CF textile exhibits significant potential in pressure sensing,self-powered operation,and motion detection,making it highly suitable for wearable electronics applications.

Sulfur Vacancies Tune the Charge Distribution of NiCo_(2)S_(4) for Boosting the Energy Density of Stretchable Yarn‑Based Zn Ion Batteries

Yarn-based batteries with the dual functions of wearable and energy storage have demonstrated promising potential in wearable energy textiles.However,it is still an urgent problem to construct efficient and flexible electrodes while optimize the configuration of yarn-based batteries to maintain excellent electrochemical performance under different mechanical deformations.Herein,NiCo_(2)S_(4-x) nanotube arrays with tunable S-vacancies are constructed on carbon yarn(CY)(NiCo_(2)S_(4-x)@CY)by a facile hydrothermal strategy.The aqueous zinc-ion batteries(ZIBs)with NiCo_(2)S_(4-x)@CY as cathodes exhibit exceptional discharge capacity(271.7 mAh g^(-1))and outstanding rate performance(70.9%capacity retention at 5 A g^(-1)),and reveal a maximum power density of 6,059.5 W kg^(-1) and a maximum energy density of 432.2 Wh kg^(-1).It is worth noting that the tunable S-vacancies promote the surface reconfiguration and phase transitions of NiCo_(2)S_(4-x),thereby enhancing the conductivity and charge storage kinetics.The high reactivity and cycling stability of NiCo_(2)S_(4-x)@CY can be related to the discharge products of S-doped NiO and CoO.Furthermore,flexible stretchable yarn-based ZIBs with wrapped yarn structures are constructed and exhibit excellent tensile stability and durability under a variety of mechanical deformations.As a proof of concept,the ZIBs integrated into the fabric show excellent electrochemical performance even in response to simultaneous stretching and bending mechanical deformations.The proposed strategy provides novel inspiration for the development of highly efficient and economical yarn-based ZIBs and wearable energy textiles.