Water‐Saturated Ion Gel for Humidity‐Independent High Precision Epidermal Ionic Temperature Sensor. Issue 16 (25th March 2022)

• Record Type: Journal Article
• Authors: Kim, Hyun Woo; Kim, Eunseo; Oh, Joosung; Lee, Hyomin; Jeong, Unyong
• Is Part Of: Advanced science. Volume 9:Issue 16(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-25
• Subjects: deformation independence -- humidity independence -- stretchable temperature sensor -- water‐saturated Ion gel -- wearable sensor; Science -- Periodicals; 505
• DOI: 10.1002/advs.202200687
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract: Although ion gels are attractive sensing materials for deformable epidermal sensors or implantable devices, their sensing performances are highly affected by environmental humidity change, so that their sensing reliability cannot be secured. This study proposes a new concept of maintaining the high‐precision temperature sensing performance of highly deformable ion gel sensors. In this approach, a hydrophobic ion gel sensing layer is kept water‐saturated by attaching a hydrogel layer, rather than attempting to completely block water penetration. This study performs experimental and theoretical investigation on water concentration in the ion gel, using the analysis of mass transportation at the interface of the ion gel and the hydrogel. By using the charge relaxation time of the ionic molecules, the temperature sensor is not affected by environmental humidity in the extreme range of humidity (30%–100%). This study demonstrates a highly deformable on‐skin temperature sensor which shows the same performance either in water or dry state and while exercising with large strains ( ε = 50%). Abstract : A highly deformable ion gel‐based temperature sensor that is not affected by environmental humidity change is fabricated by keeping a hydrophobic ion gel sensing layer to be water saturated. The sensor shows identical high‐precision temperature sensing performance either in water or dry conditions, additionally in a stretched state when attached to the elbow.