Dynamic Ag–N Bond Enhanced Stretchable Conductor for Transparent and Self-Healing Electronic Skin

Abstract

Stretchable conductors have been achieved by stacking conductive nanomaterials onto the surfaces of elastomeric substrates. However, many of them show a dramatic decrease in conductivity under strain without an efficient way for the conductive layer to release strain. Here, we report a transparent, stretchable, and self-healing conductor with excellent mechanoelectrical stability by introducing dynamic bonding between conductive nanomaterials and an elastomeric substrate. We prepare the conductor by semiembedding Ag nanowires (AgNWs) into a self-healing polydimethylsiloxane (PDMS)-based elastomer, which is modified with bipyridine (Bpy) ligand and further cross-linked by adding Zn2+ as coordinator (Zn–Bpy–PDMS). The dynamic Ag–N bonds not only improve the wettability of the substrate and facilitate the spreading of AgNWs but also reversibly break and reform to accommodate the deformation of AgNWs. As a result, the resistance increase of Zn–Bpy–PDMS/AgNWs is much smaller than that without the dynamic bonding (PDMS/AgNWs). Besides, this conductor exhibits excellent conductivity (76.2 Ω/sq) and transparency (86.6% @ 550 nm), as well as extraordinary self-healing property with a low resistance increase (ΔR/R 0 ∼ 1.4) after healing at room temperature for 1 day. This work provides insights into the future design of integrated electronic skin with transparency, stretchability, conductivity, and self-healing capability for applications in wearable optoelectronic devices.

Recent Progress in Essential Functions of Soft Electronic Skin

“…Therefore, self-healing ability can effectively endow e-skins with the long-term robustness and reliability like human skin. [230][231][232][233][234][235][236] The basic strategy to achieve the self-healing ability of e-skins is to use the self-healing materials in the fabrication of e-skins. Based on this strategy, utilizing the self-healing polymer as the device matrix can effectively repair the mechanical damage of the device.…”

3D Printed Flexible Strain Sensors: From Printing to Devices and Signals

“…Continuously, by reason of prevalent demands for silver with excellent electrical and thermal conductivity in the electronic fields, the evolvement of nano silver has become the primary choice of conductive agents for various electronic devices, including sensors. [ 95 ] In addition, the core composition of 3D printed strain sensors consists of flexible polymer matrices offering sufficient detecting range and conductive components keeping the sensitivity, which could be processed with varied configurations through DIW printing technology for meeting the universality of sensors in a variety of testing environments. Being possessed with electrical insulation, physiological inertness, and temperature resistance, PDMS elastomers have been extensively impressed on the researches of flexible strain sensors.…”

Self‐Healing Functional Electronic Devices

“…[110][111][112] E-skin has many promising applications in the fields of soft robotic systems, wearable electronics, robotic prosthetics, and artificial intelligence. [113][114][115] To improve the stability and lifespan of e-skin, self-healing capability can be a feasible solution.…”