Ultra-Sensitive Strain Sensor Based on Flexible Poly(vinylidene fluoride) Piezoelectric Film

Abstract

A flexible 4 × 4 sensor array with 16 micro-scale capacitive units has been demonstrated based on flexible piezoelectric poly(vinylidene fluoride) (PVDF) film. The piezoelectricity and surface morphology of the PVDF were examined by optical imaging and piezoresponse force microscopy (PFM). The PFM shows phase contrast, indicating clear interface between the PVDF and electrode. The electro-mechanical properties show that the sensor exhibits excellent output response and an ultra-high signal-to-noise ratio. The output voltage and the applied pressure possess linear relationship with a slope of 12 mV/kPa. The hold-and-release output characteristics recover in less than 2.5 μs, demonstrating outstanding electro-mechanical response. Additionally, signal interference between the adjacent arrays has been investigated via theoretical simulation. The results show the interference reduces with decreasing pressure at a rate of 0.028 mV/kPa, highly scalable with electrode size and becoming insignificant for pressure level under 178 kPa.

Recent Advances in Ferroelectric Nanosensors: Toward Sensitive Detection of Gas, Mechanothermal Signals, and Radiation

“…A novel ultrasensitive strain sensor, based on PVDF thin film, has been recently developed by Lu et al [79]. The proposed sensor array consisted of 16 microcapacitor units with a 4 × 4 square structure, which were patterned on polydimethylsiloxane (PDMS) substrate.…”

“…The proposed sensor array consisted of 16 microcapacitor units with a 4 × 4 square structure, which were patterned on polydimethylsiloxane (PDMS) substrate. The voltage signals of 20-300 mV were generated, when a pressure in the range of 60-150 kPa was applied to the sensor [79]. The device exhibited ultra-high sensitivity of 12 mV/kPa and extremely fast The multimodal e-skin containing the rGO/PVDF composite, discussed in the previous section, was applied in [70] for piezoelectric sensing of dynamic tactile stimuli.…”

Multidirectional Cylindrical Piezoelectric Force Sensor: Design and Experimental Validation

“…Piezoelectric materials have received considerable attention in the field of sensing [ 1 , 2 , 3 ] and energy harvesting [ 4 , 5 , 6 ] because of their flexibility, fast response speeds, as well as the properties of generating internal electric potential from mechanical deformation [ 7 , 8 ]. In particular, the electromechanical effect of these materials makes it possible to detect physical stimuli without external power, so many researchers have studied various sensors, such as force and strain sensors, using this mechanism [ 9 , 10 , 11 , 12 ]. Among these, force sensors have become more important with the development of advanced robots, such as soft robots, humanoid robots, and medical robots [ 13 , 14 , 15 , 16 , 17 , 18 ].…”

Flexible Shear and Normal Force Sensor Using only One Layer of Polyvinylidene Fluoride Film

“…Force sensors that can sense shear and normal forces have been broadly studied. These sensors typically utilize the capacitive [13][14][15], piezo-resistive [16][17][18], and piezoelectric [19][20][21] properties of materials. Of these sensors, the capacitive ones have excellent sensitivity, large dynamic range, and good spatial resolution.…”

“…In contrast, the piezoelectric ones have the characteristic advantage of being self-powered, i.e., they generate electrical signals under external mechanical inputs [22,23]. With this benefit, several studies have been performed with piezoelectric force sensors that can measure shear forces [20,21,[24][25][26]. Specifically, therein, some researchers have assembled polydimethylsiloxane (PDMS) bump structures on flat or micropillar-type polyvinylidene fluoride (PVDF) and have used electrodes of specific shapes for effective sensing, resulting in the detection of shear and normal forces.…”