Improved Flexible Triboelectric Nanogenerator Based on Tile-Nanostructure for Wireless Human Health Monitor

Triboelectric nanogenerators(TENGs)have emerged as promising candidates for integrating with flexible electronics as self-powered systems owing to their intrinsic flexibility,biocompatibility,and miniaturization.In this study,an improved flexible TENG with a tile-nanostructured MXene/polymethyl methacrylate(PMMA)composite electrode(MP-TENG)is proposed for use in wireless human health monitor.The multifunctional tile-nanostructured MXene/PMMA film,which is self-assembled through vacuum filtration,exhibits good conductivity,excellent charge capacity,and high flexibility.Thus,the MXene/PMMA composite electrode can simultaneously function as a charge-generating,charge-trapping,and charge-collecting layer.Furthermore,the charge-trapping capacity of a tile nanostructure can be optimized on the basis of the PMMA concentration.At a mass fraction of 4%PMMA,the MP-TENG achieves the optimal output performance,with an output voltage of 37.8 V,an output current of 1.8μA,and transferred charge of 14.1 nC.The output power is enhanced over twofold compared with the pure MXene-based TENG.Moreover,the MP-TENG has sufficient power capacity and durability to power small electronic devices.Finally,a wireless human motion monitor based on the MP-TENG is utilized to detect physiological signals in various kinematic motions.Consequently,the proposed performance-enhanced MP-TENG proves a considerable potential for use in health monitoring,telemedicine,and self-powered systems.

Programmable and reconfigurable humidity-driven actuators made with MXene(Ti_(3)C_(2)T_(x))-cellulose nanofiber composites for biomimetic applications

Smart actuators have a wide range of applications in bionics and energy conversion.The ability to reconfigure shape is essential for soft actuators to achieve various shapes and deformations,which is a crucial feature for next-generation actuators.Nonetheless,it is still an enormous challenge to establish a straightforward approach to creating programmable and reconfigurable actuators.MXene-cellulose nanofiber composite film(MCCF)with a brick-and-mortar hierarchical structure was produced through a vacuum filtration process.MCCF demonstrates impressive mechanical properties such as a tensile stress of 68 MPa and a Young’s modulus of 4.65 GPa.Besides,the MCCF highlights its potential for water-assisted shaping/welding due to the abundance of hydrogen bonds between MXene and cellulose nanofibers.MCCF also showcases capabilities as a humiditydriven actuator with a rapid response rate of 550°·s^(−1).Using the methods of water-assisted shaping/welding,several bionic actuators(such as flower,butterfly,and muscle)based on MCCF were designed,highlighting their versatility in applications of smart actuators.The research showcases the impressive capabilities of MXene-based actuators and offers beneficial insights for the advancement of future intelligent materials.

Performance-enhanced and cost-effective triboelectric nanogenerator based on stretchable electrode for wearable SpO2 monitoring

Recently,stretchable and wearable health monitoring equipment has greatly improved human’s daily life,which sets higher demands for portable power source in stretchability,sustainability,and biocompatibility.In this work,we proposed a stretchable triboelectric nanogenerator(TENG)based on stretchable poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)/porous carbon hybrid for oxyhemoglobin saturation(SpO2)monitoring.To combine advantages of carbon material for its high conductivity and organic electrode for its high stretchability,we spin-coated a solution of PEDOT:PSS/porous carbon onto a plasma-treated pre-stretched Ecoflex film to fabricate a stretchable electrode with rough surface.Due to its roughness and high potential difference with the dielectric material,the stretchable-electrode-based TENG exhibited better performance compared to the pristine TENG based on carbon or PEDOT:PSS material.The output voltage and current reached up to 51.5 V and 13.2μA as the carbon concentration increased.More importantly,the performance further increased under large strain(100%)which is suitable for wearable systems.Finally,the device demonstrated its application potential for powering a flexible blood oxygen monitor.This simple and cost-effective method can enhance the stretchability and stability of organic/inorganic electrode-based TENG,which paves the development of high-performance stretchable TENG.