Highly Stretchable, Hysteresis-Free Ionic Liquid-Based Strain Sensor for Precise Human Motion Monitoring

• Published in: ACS applied materials & interfaces Vol. 9; no. 2; pp. 1770 - 1780
• Main Authors: Choi, Dong Yun, Kim, Min Hyeong, Oh, Yong Suk, Jung, Soo-Ho, Jung, Jae Hee, Sung, Hyung Jin, Lee, Hyung Woo, Lee, Hye Moon
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 18-01-2017
• Subjects: Elasticity; Elastomers; Humans; Ionic Liquids - chemistry; Ions; Motion; ionic liquid; stretchable sensor; strain sensor; human motion detection; viscoelastic effect
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.6b12415

A highly stretchable, low-cost strain sensor was successfully prepared using an extremely cost-effective ionic liquid of ethylene glycol/sodium chloride. The hysteresis performance of the ionic-liquid-based sensor was able to be improved by introducing a wavy-shaped fluidic channel diminishing the hysteresis by the viscoelastic relaxation of elastomers. From the simulations on visco-hyperelastic behavior of the elastomeric channel, we demonstrated that the wavy structure can offer lower energy dissipation compared to a flat structure under a given deformation. The resistance response of the ionic-liquid-based wavy (ILBW) sensor was fairly deterministic with no hysteresis, and it was well-matched to the theoretically estimated curves. The ILBW sensors exhibited a low degree of hysteresis (0.15% at 250%), low overshoot (1.7% at 150% strain), and outstanding durability (3000 cycles at 300% strain). The ILBW sensor has excellent potential for use in precise and quantitative strain detections in various areas, such as human motion monitoring, healthcare, virtual reality, and smart clothes.