Optimized Interfacial Properties of Ionic Liquid-Based Flexible Strain Sensor for Performance Stabilization

This study developed a cost-effective flexible strain sensor with a novel composition by adding the surfactant Tween 80 to an ionic liquid based on ethylene glycol and potassium acetate. The addition of Tween 80 optimized the interfacial properties between the silicone tube (sensor substrate) and the ionic liquid (sensing material), resulting in an improved response delay of 1.23 seconds to 0.29 seconds at 50% strain. This result demonstrates interfacial optimization enhances the performance of liquid-based flexible strain sensors. Additionally, the sensor achieved extremely low hysteresis, with a 1.28% degree of hysteresis.