Facile fabrication of carbon ink-decorated melamine foams for efficient piezoelectric pressure sensors

Wearable pressure sensors have been more popular in recent years as a result of their potential applications in human motion detection and personal health monitoring. Up to now, it still remains a challenge to fabricate flexible strain sensors with low cost and high performance. In this study, a series of wearable pressure sensors with good mechanical properties and high performance have been prepared via facile method of immersing the commercial melamine foam into the carbon ink to form a three-dimensional conductive path. The experiments of step-by-step compression and cyclic compression indicated that fabricated composites carbon ink-decorated melamine foam (IMF) exhibit high sensitivity of 0.056 kPa −1 in the range of 0–7.84 kPa, 0.04 kPa −1 in the range of 7.84–31.36 kPa, and the response and recovery time of 100 ms. More significantly, the flexible IMF pressure sensors present excellent compression performance and durability after 2000 cycles. Therefore, the flexible IMF pressure sensors can monitor human activities, including joint movements, pulse, vocalization and walking, which indicates a broad application prospect for human bodily motion detection in microelectronic systems.