Highly sensitive flexible pressure sensor based on gradient microcolumn structure for ocean wave monitoring

Monitoring the dynamic fluctuations of ocean waves using highly sensitive flexible pressure sensors is a highly promising marine observation technology. In this study, we propose a flexible pressure sensor with a gradient microcolumn structure (GCS) fabricated via micro-lithography precision molding technology. The exceptional compressibility of the microcolumn structure significantly enhances the sensor's sensitivity. The GCS sequentially contacts the electrode layer from high to low, effectively modulating the contact area between the sensitive layer and the electrode layer under varying pressures. This design reduces sensitivity attenuation and broadens the detection range. The sensor achieves a wide detection range of 0–600 kPa and an ultrahigh sensitivity of 3848.57 kPa−1. It retains stable performance even after 30 days of underwater immersion and over 3500 cyclic tests. For waterproofing, we encapsulated the sensor with polydimethylsiloxane and attached it to the bottom and sides of a buoy to detect pressure variations induced by waves of different magnitudes in a water tank, enabling real-time wave monitoring. These results demonstrate its great potential for ocean wave monitoring applications.