Open AccessWater‐Saturated Ion Gel for Humidity‐Independent High Precision Epidermal Ionic Temperature Sensor
Author(s) -
Kim Hyun Woo,
Kim Eunseo,
Oh Joosung,
Lee Hyomin,
Jeong Unyong
Publication year - 2022
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.202200687
Subject(s) - humidity , materials science , ion , penetration (warfare) , ionic bonding , relative humidity , environmental chamber , analytical chemistry (journal) , chemical engineering , chromatography , chemistry , meteorology , physics , organic chemistry , operations research , engineering
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%).