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Block Copolymer‐Based Supramolecular Ionogels for Accurate On‐Skin Motion Monitoring
Author(s) -
Cho Kyung Gook,
An Sol,
Cho Dae Hyun,
Kim Jeong Hui,
Nam Jieun,
Kim Myungwoong,
Lee Keun Hyung
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202102386
Subject(s) - materials science , electronic skin , adhesive , electrical conductor , copolymer , composite material , nanotechnology , polymer , layer (electronics)
Interest in wearable and stretchable on‐skin motion sensors has grown rapidly in recent years. To expand their applicability, the sensing element must accurately detect external stimuli; however, weak adhesiveness of the sensor to a target object has been a major challenge in developing such practical and versatile devices. In this study, freestanding, stretchable, and self‐adhesive ionogel conductors are demonstrated which are composed of an associating polymer network and ionic liquid that enable conformal contact between the sensor and skin even during dynamic movement. The network of ionogel is formed by noncovalent association of two diblock copolymers, where phase‐separated micellar clusters are interconnected via hydrogen bonds between corona blocks. The resulting ionogels exhibit superior adhesive characteristics, including a very high lift‐off force of 93.3 N m −1 , as well as excellent elasticity (strain at break ≈ 720%), toughness ( ≈ 2479 kJ m −3 ), thermal stability ( ≈ 150 ° C), and high ionic conductivity ( ≈ 17.8 mS cm −1 at 150 ° C). These adhesive ionogels are successfully applied to stretchable on‐skin strain sensors as sensing elements. The resulting devices accurately monitor the movement of body parts such as the wrist, finger, ankle, and neck while maintaining intimate contact with the skin, which was not previously possible with conventional non‐adhesive ionogels.