An eco-friendly and highly sensitive loofah@CF/CNT 3D piezoresistive sensor for human activity monitoring and mechanical cotrol

Three-dimensional(3D)porous piezoresistive sensors are widely used because of their simple fabrication and convenient signal acquisition.However,because of the dependence on organic skeleton materials and the complexity of conductive coating preparation,the electrical and mechanical properties of 3D wearable piezoresistive sensors have gradually failed to accommodate many emerging fields.Here,a new flexible 3D piezoresistive sensor(NF3PS)with high sensitivity and a wide measurement range is proposed,which comprises a natural porous loofah as a flexible framework and carbon fiber/carbon nanotube(CF/CNT)multiscale composite as a conductive coating.Composed of cellulose and lignin,the irregular,porous loofah has excellent mechanical strength,elasticity,and toughness,ensuring a repeated compression/recovery behavior of the NF3PS.In addition,compared with the single-size carbon coating,the coupling of multiscale CF/CNT composite coating improves sensitivities over a range of pressures.The NF3PS demonstrates a sensitivity of 6.94 kPa^(-1) with good linearity in the pressure range of 0–11.2 kPa and maintains a sensitivity of 0.28 kPa^(-1) in an ultrawide measurement range of 11.2–84.6 kPa.Considering flexibility,robustness,and wide-ranging linear resistance variation,the feasibility of the NF3PS in human activity monitoring,mechanical control,and smart homes is verified.This work provides a novel strategy for a new generation of 3D flexible pressure sensors for improving sensitivity and measurement range and demonstrates attractive applications in wearable sensors.

Highly stable capacitive tactile sensors with tunable sensitivity facilitated by electrostatic interaction of layered double hydroxide,MXene,and Ag NWs

A capacitive tactile sensor(CTS)has been developed by assembling a double-sided patterned dielectric layer and novel electrodes.The patterned aluminium foil-supported electrode comprises zinc-aluminium layered double hydroxides(Zn AlLDH),MXene,and Ag NWs via electrostatic interaction.This flexible device enables greater structural deformation,thereby enhancing sensitivity to a wide range of pressure.The sensitivity of the CTS can be customized to meet specific requirements by matching the microstructured electrodes with the patterned dielectric layer.An optimized sensor exhibits a sensitivity of 2.752 kPa^(–1)within 30 kPa,a response time of approximately 100 ms,and a wide detection range of 0–300 kPa.The strong physical interaction among the electrode materials ensures a reliable conductive network,ensuring the long-term stability of the sensor,even after 7500 loading and unloading cycles.Furthermore,the fabricated CTS device presents a promising prospect for the integration into wearable electronics,with the ability to effectively respond to both human activities and external physical stimuli.