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This paper reports the designing and testing, as well as the processing and testing, of a flexible piezoresistive sensor for pressure-sensing applications, utilizing a composite film of graphene/polyvinylidene fluoride (Gr/PVDF). Graphene serves as the conductive matrix, while PVDF acts as both the binder and a flexible polymer matrix. The composite film was fabricated using the solution casting technique on a flexible polyethylene substrate. We investigated the impact of post-infrared annealing on the pressure response of the Gr/PVDF films. The experimental results indicated that the films IR-annealed for 2 min exhibited improved pressure sensitivity compared with the as-deposited films. The stability and durability of the sensors were assessed through the application of pressure over more than 1000 cycles. The mechanical properties of the films were examined using a universal tensile testing machine (UTM) for scenarios both with and without infrared light annealing. Raman spectroscopy was employed to analyze the quality and characteristics of the prepared nanocomposites. This study enhances our understanding of the interplay between the Gr/PVDF composite, the IR annealing effect, and the hysteresis effect in the pressure-sensing mechanism, thereby improving the piezoresistance of the Gr/PVDF nanocomposite through the infrared annealing process.

In this paper, a knittle pressure sensor was designed and fabricated by coating graphene/Polyvinylidene Fluoride nanocomposite on the knitted polyester substrate. The coating was carried out by a dip-coating method in a nanocomposite solution. The microstructure, surface properties and electrical properties of coated layers were investigated. The sensors were tested under the application of different pressures, and the corresponding sensor signals were analyzed in terms of resistance change. It was observed that the change in resistance was 55% kPa−1 with a sensitivity limit of 0.25 kPa. The sensor model was created and simulated using COMSOL Multiphysics software, and the model data were favorably compared with the experimental results. This investigation suggests that graphene-based nanocomposites can be used in knittle pressure sensor applications.

A flexible piezoresistive sensor was developed as an accelerometer based on Graphene/PVDF nanocomposite to detect low-frequency and low amplitude vibration of industrial machines, which may be caused due to misalignment, looseness of fasteners, or eccentric rotation. The sensor was structured as a cantilever beam with the proof mass at the free end. The vibration caused the proof mass to accelerate up and down, which was converted into an electrical signal. The output was recorded as the change in resistance (response percentage) with respect to the acceleration. It was found that this accelerometer has a capability of detecting acceleration up to 8 gpk-pk in the frequency range of 20 Hz to 80 Hz. The developed accelerometer has the potential to represent an alternative to the existing accelerometers due to its compactness, simplicity, and higher sensitivity for low frequency and low amplitude applications.