Soft, flexible conductivity sensors for ocean salinity monitoring
Shao‐Hao Lu, Yi Li, Xueju Wang
Abstract
) can potentially cause corrosion and dissolution of the sensors, negatively impacting their performance and durability. In this work, we develop soft, flexible conductivity sensors made of gold (Au) electrodes and systematically study their electrochemical behaviors in sodium chloride (NaCl) solutions to prevent chloride-induced corrosion and enhance their sensitivity for marine environmental monitoring. The causes of gold chlorination reactions and polarization effects are identified and effectively prevented by analyzing the effects of direct current (DC) and alternating current (AC) voltages, AC frequencies, and exposed sensing areas of the conductivity (salinity) sensors. Accordingly, a performance diagram is constructed to provide guidance for the selection of operation parameters for the salinity sensor. We also convert the varying impedance values of salinity sensors at different salinity levels into output voltage signals using a voltage divider circuit with an AC voltage (0.6 V) source. The results offer an assessment of the accuracy and response time of the salinity sensors, as well as their potential for integration with data transmission components for real-time ocean monitoring. This study has important implications for the development of soft, flexible, Au-based electrochemical sensors that can operate efficiently in diverse biological fluids and marine environments.