A low-cost piezoresistive pressure sensor with embedded spoke-like electrodes for enhanced linearity and wide dynamic range

초록

This study presents a novel piezoresistive pressure sensor featuring a flexible substrate and a uniquely embedded spoke-like circular electrode design. The electrodes are fully enclosed within a composite membrane of multi-walled carbon nanotubes (MWCNTs) and polydimethylsiloxane (PDMS), forming a sandwich-like (SS) structure. This embedded layout promotes uniform stress distribution and enhances the piezoresistive effect, resulting in superior sensing performance. Unlike conventional surface-mounted electrodes, the SS configuration improves structural integrity and mechanical stress dispersion, leading to greater sensitivity, linearity, and long-term durability. Experimental results confirm that the sensor achieves a high sensitivity of approximately 1.18 mV/kPa and excellent linearity with an R-2 value of 0.998 across a broad pressure range (0-300 kPa). It also exhibits low hysteresis (similar to 0.012 %), excellent repeatability (RSD approximate to 0.108 %), and fast response and recovery times of 5.56 ms and 3.58 ms, respectively. These performance metrics outperform many previously reported flexible pressure sensors. The SS design's reliability and precision make it highly suitable for advanced applications such as wearable electronics, human-machine interfaces, and biomedical monitoring. Overall, the proposed embedded electrode structure shows significant potential for next-generation pressure sensing technologies that require accuracy, flexibility, and real-time responsiveness.

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