High-performance piezoresistive flexible pressure sensor based on wrinkled microstructures prepared from discarded vinyl records and ultra-thin, transparent polyaniline films for human health monitoring

Abstract

Flexible piezoresistive pressure sensors have attracted a great deal of attention because of their potential applications in areas such as human motion detection and health monitoring. The attachment of conducting polymers to the surface of microstructured Polydimethylsiloxane (PDMS) thin films is one effective method of preparing flexible pressure sensors. However, enhancing the interfacial adhesion of the conductive polymer and PDMS to prevent flaking and improve performance stability is a key issue. Here, we replicated the surface of a discarded vinyl record to create a PDMS film with wrinkled microstructures, reducing manufacturing costs and enabling the use of waste. A flexible, transparent and microdefect-free polyaniline film (PANI) with a thickness of 320 nm was prepared. The protonated PANI film (PPF) was tightly adhered to the microstructured surface of the PDMS film to prepare a PPF@PDMS flexible pressure sensor. The pressure-sensitive performance of the sensor remained stable after fatigue testing of 7000 loads, which proves the strong adhesion of the two films. Based on its high sensitivity (0.24 kPa⁻¹), low detection limit (2 Pa), and fast response capability (15 ms), the sensor can detect weak physiological behaviours (breathing, pulse) as well as large body movements (finger bending, finger pressing, etc.). Cyclic vibration waves from the engine can also be recognized. The excellent performance demonstrates the potential application of the PPFP sensor in the field of human health monitoring.