Planar microphone based on piezoelectric electrospun poly(γ-benzyl-α,L-glutamate) nanofibers

Wang

et al. 2019

Adv Funct Materials

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This study reports a self-powered pressure sensor based on a monocharged electret nanogenerator (MENG). The sensor exhibits great advantages in terms of high reliability, ease of fabrication, and relatively high sensitivity. The working mechanism of the MENG sensor is studied by both theoretical derivations and finite element analyses to determine the electric potential distribution during the device operation. The MENG sensor exhibits a stable open circuit voltage ≈10 V at a 30.8 kPa pressure and a corresponding sensitivity of 325 mV kPa −1 . The stability testing result shows that the device has only ≈5% attenuation after 10 000 cycles of repeated testing at 30.8 kPa pressure. Furthermore, it is found that the MENG sensor responds not only to a dynamic force but also a static force. Finally, a sensor array consisting of nine MENG sensor elements is fabricated. The testing results from the sensor array also reveal that a single touch of the sensor element can immediately light up an LED light at the corresponding position. This device holds great promise for use in future tactile sensors and artificial skin applications.

Section: Resultsmentioning

confidence: 99%

A Monocharged Electret Nanogenerator‐Based Self‐Powered Device for Pressure and Tactile Sensor Applications

Gong

Wang

et al. 2019

Adv Funct Materials

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“…Previously, many researchers have utilized a uniaxial stretching method to process PLLA film and show piezoelectricity along the shear direction of PLLA film . Recently, we reported that electrospun poly(γ‐benzyl‐α, L‐glutamate fibers can show piezoelectricity along the d 33 direction and can be used in microphone sensor applications . In this paper, we report for the first time that the electrospun PLLA nanofibers can show piezoelectricity along the fiber length direction (d 33 ) after electrospinning.…”

Section: Introductionmentioning

confidence: 87%

Electrospun Poly(l‐Lactic Acid) Nanofibers for Nanogenerator and Diagnostic Sensor Applications

Zhao

Huang

et al. 2017

Macro Materials & Eng

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This paper presents for the first time that poly(l-lactic acid) (PLLA) nanofibers can show the piezoelectricity along the fiber direction (d 33 ) by using an electrospinning method. First, the electrospun fiber bundles are characterized by scanning electron microscope, X-ray, and piezoelectric coefficient measurements. The data show that the supercritical CO 2 treatment can greatly enhance the piezoelectricity of electrospun PLLA fibers, which can be resulting from the increased crystallinity of the fibers. Later, it is found that the electrospun PLLA fiber can generate a current of 8 pA and a voltage of 20 mV by a simple push-release process. Further, a single PLLA fiber-based blood pulse sensor is also fabricated and tested and shows around a 2 pA output for blood pulse. Due to easy fabrication and relatively simple structure, this device enables a broad range of promising future applications in the medical sensor area.

Monocharged Electret Generator for Wearable Energy Harvesting Applications

Gong

Wang

Advanced Sustainable Systems

et al. 2018

Polytetrafluoroethylene (PTFE)‐based electret materials have emerged as one of the most widely used materials in underwater transducer, microphone, and transistor applications. In this paper, it is shown for the first time that a monocharged (single type, electron) PTFE electret material can be used in energy harvesting and self‐powered device applications, such as wristband and shoe insole devices. At first, a theory based on the electrostatic effect is derived for the first time for monocharged electret generator (MCEG). For a hand‐shaking movement, the MCEG‐based wristband device can generate an output voltage and current of 14 V and 0.65 µA, respectively. Furthermore, it is found that the MCEG‐based shoe insole device can generate a maximum output voltage of 178 V and a current of 2.85 µA during walking. The maximum harvested power obtained is ≈35.63 µW in shoe insole‐based devices under a resistor load. Additionally, the power generated from the shoe insole device can light up 55 light‐emitting diodes with a single step of walking. Because of the relatively large output power density, ease of fabrication, and chemical stability, this device shows great promise for wearable self‐powered device applications.