Wide measurement range and high sensitivity spongy MWCNT/polydimethylsiloxane pressure sensor based on a single-electrode enhanced triboelectric nanogenerator

Flexible pressure sensors have broad application prospects,such as human motion monitoring and personalized recognition.However,their applicability is limited by complex structures,low output performance,low sensitivity,and narrow measurement range.In this study,we report a single-electrode spongy triboelectric sensor(SSTS)mainly composed of spongy composite multi-walled carbon nanotubes/polydimethylsiloxane(MWCNT/PDMS)film and conductive fabric,which can simultaneously generate contact electrification and electrostatic induction coupling in a single-electrode contact-separation mode.The SSTS combines the triboelectric effect,properties of doping material,and spongy porous structure(soft sugar as a sacrificial template).An SSTS with an MWCNT content of 10 wt%and a porosity of 64%exhibits high sensitivity,a wide measurement range,and excellent linearity.It also displays two sensitivity regions(slopes):1.324 V/kPa from 1.5 to 28 kPa in the low-pressure range and 0.096 V/kPa from 28 to 316.5 kPa in the high-pressure range,with linearities of 0.980 and 0.979,respectively.Furthermore,the SSTS delivers a high-performance output and high stability,thus enhancing the monitoring of hand pressure changes,human movement,personalized spatial recognition,and other detection tasks.This new strategy for human motion monitoring shows great potential in the healthcare fields,sports rehabilitation,and human-computer interactions.

A novel wide-range precision instrument for measuring three-dimensional surface topography

We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional (3D) surface topography measurement was composed of a high precision displacement sensor based on the Michelson interference principle, a 3D platform based on vertical scanning, a measuring and control circuit, and an industrial control computer. It was a closed loop control system, which changed the traditional moving stylus scanning style into a moving platform scanning style. When the workpiece was measured, the lever of the displacement sensor returned to the balanced position in every sample interval according to the zero offset of the displacement sensor. The non-linear error caused by the rotation of the lever was, therefore, very small even if the measuring range was wide. The instrument can measure the roughness and the profile size of a curved surface.

Recent Development of Dielectric Elastomer Transducers and Potential Applications

Power generation using dielectric elastomer transducers is cheap, light, stackable, easy to install, and highly efficient. Also, since the dielectric elastomer transducer is an actuator developed into an artificial muscle, if the DE motor is further developed, it might be possibly be able to drive a vehicle. Efficient robot driving, various industrial machines and the use of dielectric elastomer sensors to optimize the driving may also help solve the above problems from the perspective of eco-driving. This paper describes the latest level of development of dielectric elastomers, their main problems and solutions to these problems, and their potential applications. The possibilities and concrete plans for building local global smart cities (including local generation power for local consumption), efficient transportation, and environmental monitoring systems utilizing dielectric elastomers are also discussed.

Porous fiber paper and 3D patterned electrodes composed high-sensitivity flexible piezoresistive sensor for physiological signal monitoring

The research on flexible pressure sensors has drawn widespread attention in recent years,especially in the fields of health care and intelligent robots.In practical applications,the sensitivity of sensors directly affects the precision and integrity of weak pressure signals.Here,a pressure sensor with high sensitivity and a wide measurement range composed of porous fiber paper and 3D patterned electrodes is proposed.Multi-walled carbon nanotubes with excellent conductivity were evenly sprayed on the fiber paper to form the natural spatial conducting networks,while the copper-deposited polydimethylsiloxane films with micropyramids array were used as electrodes and flexible substrates.Increased conducting paths between electrodes and fibers can be obtained when high-density micro-pyramids fall into the porous structures of the fiber paper under external pressure,thereby promoting the pressure sensor to show an ultra-high sensitivity of 17.65 kPa^(-1)in the pressure range of 0–2 kPa,16 times that of the device without patterned electrodes.Besides,the sensor retains a high sensitivity of 2.06 kPa^(-1)in an ultra-wide measurement range of 150 kPa.Moreover,the sensor can detect various physiological signals,including pulse and voice,while attached to the human skin.This work provides a novel strategy to significantly improve the sensitivity and measurement range of flexible pressure sensors,as well as demonstrates attractive applications in physiological signal monitoring.