Salt-Enhanced Biocompatible Solid Polymer Electrolytes Humidity Sensor

Abstract We present a biocompatible, ultrathin, porous freeze-drying Polyvinyl Alcohol/Hyaluronic Acid/Polylactic-co-glycolic acid/Magnesium Sulfate (FD-PHLM) composite-based high sensitivity humidity sensor, suitable for human interaction applications. Magnesium Sulfate was introduced to form solid polymer electrolytes and Electric Double Layer. The freeze-drying process produces a porous structure that leads to enhanced sensitivity and rapid responses (0.807 s response time, 0.683 s decay time) to humidity changes, with a sensitivity of 11.09 pF/%RH in the 10-90%RH range. The sensor utilizes materials that are non-toxic to both the human body and the environment, thereby expanding its application range to include contactless click sensing and exercise state sensing. The FD-PHLM sensor is a substantial innovation in humidity detection, combining biocompatibility, environmental friendliness, quick response time and enhanced sensitivity, aligning with the needs of human-centric environmental and health monitoring systems. This research contributes significantly to the development of efficient, environmentally friendly human activity monitoring tools.