A Highly‐Adhesive and Self‐Healing Elastomer for Bio‐Interfacial Electrode

Abstract

Stretchable electrodes are playing important roles in the measurement of bio‐electrical signals especially in wearable electronic devices. These electrodes usually adopt commercial elastomers such as polydimethylsiloxane or polystyrene‐ethylene‐butylene‐styrene as substrates, which result in poor stability and reliability due to weak interfacial adhesion between electrodes and human skin. Here, dopamine is introduced into the hydrogen bonding based elastomer as pendent groups. The elastomer shows both mechanical strength and adhesion strength at the same time. It exhibits high stress at break (1.9 MPa) and high fracture strain (5100%). Significantly, it exhibits a high adhesive strength (≈62 kPa) and underwater adhesive strength (≈16 kPa) with epithelial tissue. Thus, a stretchable bio‐interfacial electrode is fabricated by spray‐coating silver nanowires on the elastic substrate, which is stretchable, self‐healable, and highly adhesive and suitable for electromyogram measurement.

Bioinspired modified graphene oxide/polyurethane composites with rapid self-healing performance and excellent mechanical properties

“…Nowadays, marine mussel has aroused considerable attention in various elds, especially in self-healing materials. [31][32][33] The mussel-inspired self-healing materials originate from the fact that the high content of catechol groups in the mussel adhesive proteins can form strong covalent and non-covalent bonds with various surfaces, 32,34,35 thereby possessing outstanding adhesion ability. Especially, the dihydroxy of catechol groups can form bidentate hydrogen and metal-mediated reversible coordination, which is important for the self-healing process.…”

“…Especially, the dihydroxy of catechol groups can form bidentate hydrogen and metal-mediated reversible coordination, which is important for the self-healing process. 32,33 Moreover, mussel adhesive protein exhibits outstanding adhesion properties in an extremely harsh environment of the ocean, 36 and the mussel-inspired catechol groups can be well-bonding and maintain high adhesion underwater. 37 Inspired by the above-mentioned features, it is expected to design an HTPB-based PU with underwater and room-temperature self-healing ability based on disulde bonds and mussel-mimetic hydrogen bonds, which is signicant and consistent with its long-term working environment.…”

Hydrogen Bonding in Self-Healing Elastomers

“…An elastomer with dopamine moieties as pendent groups was synthesized and showed good mechanical strength (1.9 MPa stress at break and 5100% fracture strain) and adhesion strength (≈62 kPa in air and ≈16 kPa underwater) at the same time. 78 Because of the excellent adhesive strength of the elastomer with an epithelial tissue, a stretchable, self-healable, and highly adhesive bio-interfacial electrode for electromyogram measurement was fabricated by spray-coating silver nanowires on the elastic substrate. After cutting the electrode, the electromyogram signal immediately became weak with a low signal/noise ratio due to the resistance increasing.…”

“… (a) Ambulatory EMG monitoring when the DAE electrode was cut off and after healing. 78 (b) Photographs showing the HELIOS device healed immediately after a puncture. 79 (c) Comparative gas-separation performance of original polymer membranes (blue) and polymer membranes after being cut and healing (orange), CO 2 permeability (up), and CO 2 /N 2 selectivity (bottom).…”

“…(e) Cycle performances and coulombic efficiency of the Si electrode with a varied SHP–PEG binder. 81 (a) Reproduced with permission from ref ( 78 ). Copyright 2018, Wiley-VCH.…”