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Highly Sensitive On‐Skin Temperature Sensors Based on Biocompatible Hydrogels with Thermoresponsive Transparency and Resistivity
Author(s) -
Park Tae Hyun,
Park Seongjin,
Yu Seunggun,
Park Sangun,
Lee Junseok,
Kim Sunho,
Jung Youngmee,
Yi Hyunjung
Publication year - 2021
Publication title -
advanced healthcare materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.288
H-Index - 90
eISSN - 2192-2659
pISSN - 2192-2640
DOI - 10.1002/adhm.202100469
Subject(s) - materials science , biocompatible material , self healing hydrogels , transparency (behavior) , optical transparency , transmittance , thermoresponsive polymers in chromatography , electrical resistivity and conductivity , optoelectronics , conductivity , atmospheric temperature range , composite material , biomedical engineering , nanotechnology , polymer chemistry , computer science , chemistry , phase (matter) , electrical engineering , medicine , physics , computer security , organic chemistry , engineering , reversed phase chromatography , meteorology
The development of electrically responsive sensors that interact directly with human skin and at the same time produce a visual indication of the temperature is in great demand. Here, we report a highly sensitive electronic skin (E‐skin) sensor that measures and visualizes skin temperature simultaneously using a biocompatible hydrogel displaying thermoresponsive transparency and resistivity resulting from a temperature dependence of the strength of the hydrogen bonding between its components. This thermoresponsive hydrogel (TRH) showed a temperature dependence of not only the proton conductivity but also of its transmittance of light through a change in polymer conformation. We were able to use our TRH temperature sensor (TRH‐TS) to measure temperature in a wide range of temperatures based on a change in its intrinsic resistivity (−0.0289 °C −1 ) and to visualize the temperature due to its thermoresponsive transmittance (from 7% to 96%). The TRH‐TS exhibited high reliability upon multiple cycles of heating and cooling. The on‐skin TRH‐TS patch is also shown to successfully produce changes in its impedance and optical transparency as a result of changes in skin temperature during cardiovascular exercise. This work has shown that our biocompatible TRH‐TS is potentially suitable as wearable E‐skin for various emerging flexible healthcare monitoring applications.