Electrospining Machine: Wearable Pulse Sensor Design Based on Flexible Piezoelectric Nanofiber Membrane

On October 28, 2024, Cao Congjun published the latest research paper, "Design of Wearable Pulse Sensor Based on Flexible Piezoelectric Thin Film," in the Journal of Electronic Measurement and Instrumentation. Significant progress has been made in the design of wearable pulse sensors based on flexible piezoelectric thin films, which is expected to advance medical clinical research and interventional diagnosis and treatment research for cardiovascular and other diseases.

method

1. P(VDF-TrFE) Nanofiber Membrane preparation:

P(VDF-TrFE) Nanofiber Membrane with a thickness of 48 um was prepared as the sensor substrate by solution casting method, and the conductive electrodes were printed on the surface of the prepared piezoelectric Nanofiber Membrane by using screen printing technique.

2. Electrode Polarization:

The gold-sprayed film is sandwiched between parallel electrodes and immersed in dimethylsilicone oil, allowing the P(VDF-TrFE) Nanofiber Membrane to develop piezoelectric properties.

3. Conductive Electrode Printing: 

Screen printing technology is utilized to print conductive electrodes on the surface of the prepared piezoelectric Nanofiber Membrane.

Research Highlights

Bionic structural design: 

A novel graphene flexible stress sensor is designed with reference to the spider web structure, with excellent resonance capability and overall structural robustness.

Reducing the influence of environmental signals by using a shielding layer:

A mesh shielding layer is introduced and arranged on the surface of the piezoelectric sensor, which can reduce the influence of environmental signals and improve the accuracy and stability of the pulse wave signal acquisition. The outermost layer is a mesh signal shielding layer, which is used to reduce the influence of ambient signals; the second layer is an insulating layer, which can effectively isolate the conductive electrodes and the shielding layer, preventing short circuits between the electrodes.

Circular Array Sensor:

Compared with the square sensor, it has higher sensitivity and clarity, and better detection performance. This circular structure is closer to the actual operation of pulse cutting in Chinese medicine, no matter how the sensor rotates, it can accurately monitor the pulse signals of the three parts of the inch, Guan, and ulna, which can better adapt to the shape of the hand and pulse position of different individuals.

Signal Conditioning Circuit:

Adopting five parts, including negative power supply circuit. charge amplifier circuit, 50 HZ lF trap circuit, low-pass filter circuit and level shifter circuit, itis able to mitigate the 50 Hz lF interference and high-frequency noise interference, and successfully amplify the average peak voltage to display a clear and stable pulse waveform. testing their dielectric spectrograms.

Characterization Methods

Dielectric Performance Test:

The dielectric performance of the P(VDF-TrFE) Nanofiber Membrane was evaluated by testing its dielectric frequency spectrum.

Piezoelectric Performance Test:

The piezoelectric coefficient of the P(VDF-TrFE) Nanofiber Membrane was tested using a quasi-static d33 measuring instrument.

Ferroelectric Performance Test:

The ferroelectric performance of the P(VDF-TrFE) Nanofiber Membrane was tested through the hysteresis loop.

Paper link: https://link.cnki.net/urlid/11.2488.tn.20241025.2057.006