Highly Sensitive Flexible Iontronic Pressure Sensor for Marine Pressure Monitoring

Flexible pressure sensors hold considerable promise for applications in marine pressure detection due to their highly conformal capability to accommodate the nonplanar surface. However, fabricating a flexible pressure sensor with heightened sensitivity under substantial hydrostatic pressure in oceanic environments presents an enormous challenge due to the large underwater electromechanical noise. Herein, a flexible iontronic pressure sensor with micropillars was developed to maintain high sensitivity under large pressure loads. This sensor demonstrates excellent sensitivity (14.02 kPa<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}$ </tex-math></inline-formula>, 9.60 kPa<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}$ </tex-math></inline-formula>) and linear response (R<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{{2}} =0.9956$ </tex-math></inline-formula>, 0.9901) in air and water, respectively. The pressure sensor exhibits the capability to detect minimal water depth changes of 2 cm, offering discernible responses to pressures spanning from a few kPa to several hundred kPa. Even after its immersion in water for 25 days and 2000 testing cycles, the sensor maintains a high degree of performance consistency. This demonstrates the promising application prospects in autonomous underwater vehicles, diving equipment and marine life monitoring platforms.