Polyvinylpyrrolidone （PVP） nanofibers were processed by magnetic-field-assisted electrospinning （MFAES） technique. Since electric field intensity was one of the most important parameters influencing fiber morpholo...Polyvinylpyrrolidone （PVP） nanofibers were processed by magnetic-field-assisted electrospinning （MFAES） technique. Since electric field intensity was one of the most important parameters influencing fiber morphology, the research aimed to study how electric field intensity affects fiber morphology in MFAES technique. The experimental results revealed that the distribution of diameter widened while the average diameter of PVP fibers decreased and the degree of the alignment reduced with the increase of electric field intensity. However, the fibers would be conglutinated together when the electric field intensity was too low. Also, the increase of working distance made the average diameter and the degree of the alignment increase slightly under the same electric field intensity, but the fibers could be partially curved instead of being fully straight if the working distance was too long. It was also indicated that maintaining the electric field intensity at 1 kV/cm With the voltage-distance combinations of 12 kV-12 cm （for 12wt% PVP） and 15 kV-15 cm （for 14wt% PVP） among all other combinations would result in the optimal alignment as well as a narrow size distribution of the fibers.展开更多
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 aff...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.展开更多
基金Fund by the Youth Foundation of the North University of China(2012)the Project of Graduate Innovation of Shanxi Province(20133102)
文摘Polyvinylpyrrolidone （PVP） nanofibers were processed by magnetic-field-assisted electrospinning （MFAES） technique. Since electric field intensity was one of the most important parameters influencing fiber morphology, the research aimed to study how electric field intensity affects fiber morphology in MFAES technique. The experimental results revealed that the distribution of diameter widened while the average diameter of PVP fibers decreased and the degree of the alignment reduced with the increase of electric field intensity. However, the fibers would be conglutinated together when the electric field intensity was too low. Also, the increase of working distance made the average diameter and the degree of the alignment increase slightly under the same electric field intensity, but the fibers could be partially curved instead of being fully straight if the working distance was too long. It was also indicated that maintaining the electric field intensity at 1 kV/cm With the voltage-distance combinations of 12 kV-12 cm （for 12wt% PVP） and 15 kV-15 cm （for 14wt% PVP） among all other combinations would result in the optimal alignment as well as a narrow size distribution of the fibers.
基金supported by the National Key R&D Program of China(Grant Nos.2019YFE0120300,2019YFF0301802)National Natural Science Foundation of China(Grant Nos.52175554,62101513,51975542)+3 种基金Natural Science Foundation of Shanxi Province(Grant No.201801D121152)Shanxi“1331 Project”Key Subject Construction(Grant No.1331KSC)National Defense Fundamental Research ProjectResearch Project Supported by Shan Xi Scholarship Council of China(Grant No.2020-109)。
文摘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.
