Development of fast-response flexible temperature sensor for air–sea interface monitoring

Sea surface temperature plays a crucial role in the exchange of heat, gases, and materials between the ocean and atmosphere, profoundly influencing global climate, marine ecosystems, and atmospheric circulation. However, temperature variations at the air–sea interface are rapid and highly unstable, being affected by multiple dynamic factors, posing significant challenges for real-time monitoring. In this work, a rapid-response flexible temperature sensor was developed using polyimide film as the substrate. Based on the thermal expansion mechanism and finite element analysis, the optimal sensor structure and material composition were determined. The sensor was fabricated via screen-printing technology, employing a acrylic copolymer and polydimethylsiloxane (PDMS) as the composite matrix, with carbon black and nickel serving as conductive fillers. A PDMS encapsulation layer was applied to enhance waterproofing performance. Within the temperature range of 0–35 °C, the sensor exhibited a high temperature coefficient of resistance of 4.82%/°C, an excellent temperature resolution of 0.05 °C, an ultrafast response time of 40 ms, outstanding thermal stability over more than 500 heating–cooling cycles, and strong insensitivity to external stimuli such as bending, humidity, and pressure. When integrated into a marine buoy system for testing, the sensor accurately detected temperature fluctuations, demonstrating great potential for temperature monitoring at the air–sea interface.