Synergistic Enhancement Properties of a Flexible Integrated PAN/PVDF Piezoelectric Sensor for Human Posture Recognition

Abstract

The flexible pressure sensor has attracted much attention due to its wearable and conformal advantage. All the same, enhancing its electrical and structural properties is still a huge challenge. Herein, a flexible integrated pressure sensor (FIPS) composed of a solid silicone rubber matrix, composited with piezoelectric powers of polyacrylonitrile/Polyvinylidene fluoride (PAN/PVDF) and conductive silver-coated glass microspheres is first proposed. Specifically, the mass ratio of the PAN/PVDF and the rubber is up to 4:5 after mechanical mixing. The output voltage of the sensor with composite PAN/PVDF reaches 49 V, which is 2.57 and 3.06 times that with the single components, PAN and PVDF, respectively. In the range from 0 to 800 kPa, its linearity of voltage and current are all close to 0.986. Meanwhile, the sensor retains high voltage and current sensitivities of 42 mV/kPa and 0.174 nA/kPa, respectively. Furthermore, the minimum response time is 43 ms at a frequency range of 1–2.5 Hz in different postures, and the stability is verified over 10,000 cycles. In practical measurements, the designed FIPS showed excellent recognition abilities for various gaits and different bending degrees of fingers. This work provides a novel strategy to improve the flexible pressure sensor, and demonstrates an attractive potential in terms of human health and motion monitoring.

Recent Progress in Flexible Pressure Sensor Arrays

“…Piezoelectricity is another transduction method for pressure sensing. Flexible piezoelectric pressure sensors can convert mechanical stimuli into electrical signals [ 41 ]. The piezoelectric effect refers to electric charge production due to the occurrence of electrical dipole moments from mechanical force with a non-centrosymmetric crystal structure, such as zinc oxide (ZnO), cadmium sulfide (CdS), and gallium nitride (GaN).…”

Enhanced the dielectric and piezoelectric properties of polyacrylonitrile piezoelectric composite fibers filled with ionic liquids

“…[10][11][12] Compared with ceramics and metal oxides, polymer materials exhibit higher electric field strength and breakdown capability. [13][14][15] Based on these characteristics, it can be used in more fields according to the needs of the environment.…”

Flexible Sensors Array Based on Frosted Microstructured Ecoflex Film and TPU Nanofibers for Epidermal Pulse Wave Monitoring

“…The devices used for PWV detection in clinical settings have the characteristics of large volume and inconvenient operation, which limits the application scenarios of clinical devices in future personalized autonomous health monitoring. With the vigorous development of flexible sensing technology in the past few years, numerous flexible sensors have been developed to monitor various signals related to people, including body movements [ 3 , 4 ], postures [ 5 ], and other human physiological signals (e.g., respiration [ 6 , 7 , 8 ], ballistocardiogram [ 9 ], epidermal pulse wave [ 10 , 11 ]). As one of the most important physiological signals, pulse wave parameters (e.g., strength, shape, rhythm, duration, width, and transition time) lend insights into individuals’ health [ 12 ].…”