A Novel Ionic-Liquid Strain Sensor for Large-Strain Applications

A novel liquid strain sensor was developed by using "room-temperature ionic liquid" as the piezoresistive gauge material. Polydimethylsiloxane, with microchannels, was used to form gauge structures, and carbon fibers were used as electrodes. The strain performance was examined by electrochemical impedance spectroscopy at room temperature, and curve flitting was applied for explaining the strain response. The results show that a maximum true strain of up to 55% can be measured with good repeatability. A parabolic relationship between the real part of the impedance (Z(re)) and the true strain (epsilon) is observed, mainly due to the resistance change of the electrolyte. The demonstrated ionic-liquid-based strain sensor is of low cost, is environmentally friendly, and is promising for a wide variety of applications.