Stretchable and Directly Patternable Double-Layer Structure Electrodes with Complete Coverage

Abstract

Stretchable electrodes are widely used in next-generation wearable electronics. Recent studies incorporated designs that help rigid electrodes attain stretchability. However, these structures exhibited unsatisfactory charge/signal extraction efficiency because of their low areal fill factor. Additionally, they cannot be photolithographically patterned on polymer substrates because of their low adhesion, requiring additional complicated fabrication steps. We developed photolithographically patternable stretchable electrodes with complete coverage and enhanced charge-extraction efficiency. The electrodes, comprising double layers, included a chemically treated Ag nanowire mesh and Au thin film. The interfacial linker role of polyvinylpyrrolidone chemically strengthened the interfacial bonds, and the reinforced concrete structure of nanowire-embedded metal thin films enhanced the mechanical properties. Therefore, the electrodes provided superior efficiency and stability in capturing physical, electromagnetic, and electrophysiological signals while exceeding the existing stretchable electrode limits. A broad range of applications are foreseen, such as electrocardiogram sensing electrodes, strain sensors, temperature sensors, and antennas.

Mechanically-Guided 3D Assembly for Architected Flexible Electronics

“…3D flexible electronics manufactured through mechanically-guided methods have emerged as promising tools for in vivo monitoring of physiological signals for living organisms, such as tissues and organs. ,,,,,,− For example, 3D piezoelectric microsystems (Figure a) were fabricated for implantable monitoring of muscle activities (e.g., trotting and climbing), providing platforms for in vivo biological interactions without obvious irritations or mechanical constraints . Other 3D forms with high stretchabilities were exploited in wireless skin-compatible electronic sensors, enabling the tracking of spatial motions and the monitoring of electrophysiological signals .…”

Extremely Stable Ag‐Based Photonics, Plasmonic, Optical, and Electronic Materials and Devices Designed with Surface Chemistry Engineering for Anti‐Tarnish

“…[ 5–7 ] Furthermore, owing to the various dimensions of Ag structures, such as 3D (bulk or powder), 2D (nanoplates), 1D (nanowires; NWs), and 0D (nanocrystals; NCs), and films, which allow for tunable light absorption coefficients, optical bandgaps, and electron transport mechanisms, Ag‐based research has attracted significant attention in the fabrication of biosensors, healthcare devices, and flexible electrodes. [ 8–14 ]…”

Static electricity-based motion artifact-free electrocardiography with novel Ti3C2Tx MXene/Ag nanowire/polymer hybrid dry electrodes

“…The approach to the development of dry electrodes closely mirrors that of existing flexible electrodes, with mechanical flexibility being a cardinal requirement to ensure conformal contact with the skin. 10 A plethora of conductive materials, including flexible or stretchable electrodes formed with such materials, could be considered in the development of dry electrodes. Further, for the formation of an electrode film, exceptionally thin or elastomeric polymer films such as polyethylene terephthalate, polyimide, polyethylene naphthalate, silicone, or polyurethane can be employed to enable conformal contact with the three-dimensional curvature of the skin.…”

“…Several validations have been completed or are currently in progress as electrode materials for flexible devices, suggesting their considerable potential for dry electrode applications. [10][11][12][13][14][15] However, expansive conductive surface coverage and contact stability are the critical prerequisites to achieving low contact impedance with the skin when employing them as dry electrodes for ECG.…”