Skin Electronics from Biocompatible In Situ Welding Enabled By Intrinsically Sticky Conductors

Abstract

Welding usually involves high temperatures, toxic solvents, or conditions not compatible with human bodies, which severely limit the fusion of electronics and human tissues. To achieve direct welding of electronics on human skin, the intrinsically sticky conductors that can simultaneously achieve metal‐grade electrical conductivity (≈41 7000 S m −1 ), hydrogel‐grade stretchability (>900% strain), and self‐adhesiveness (1.8 N cm −1 ) are reported. The sticky conductors composed of gallium indium alloy and acrylate polymer adhesives have a surface‐enriched structure, which can form instant mechanical and electrical connections with different surfaces through gentle pressure without involving conditions that may damage human tissues. Based on the sticky conductors, the in situ welding of electronics on the skin is realized. To demonstrate the feasibility of in situ welding, electronic tattoos are achieved for movement monitoring. Intrinsically sticky electrodes that can resist drying and simultaneously deform with the skin for electrophysiological measurement are also developed.

Stretchable conductors for stretchable field-effect transistors and functional circuits

“…20(b)). 206 Additionally, it is not desiccated even after extensive air exposure. Furthermore, by varying the size of the LM particles, the conductors’ characteristics might be changed.…”

“…Widely used to manufacture high-resolution electronic circuits, screen printing is gradually emerging as a promising approach for producing array patterns. 196,206,459…”

“…Widely used to manufacture high-resolution electronic circuits, screen printing is gradually emerging as a promising approach for producing array patterns. 196,206,459 A schematic drawing of the screen-printing setup is present in Fig. 26(a), in which the screen mesh is placed over the substrate.…”

“…26(c)). 206 Additionally, manually applying these stretchable circuits to surfaces can lead to imprecise and non-uniform deformations that influence performance. Nevertheless, stretchable-substrate circuitry is a hopeful technology for non-developable and small-area devices due to its advanced versatility.…”

Liquid metal enabled conformal electronics

“…Copyright@2022, Wiley (D) Schematic illustrations of the structure of the SLMC and the LM-PSA composites. (Tang et al, 2022a) Copyright@2022, Wiley (E) Schematic illustration of the fabrication of SEA using screen printing (Dong et al, 2021). Copyright@2021, Wiley (F) Schematic of the formation of LM nanoparticles (LMPnano) at the surface of existing micrometer-sized LM particles (LMPs) via acoustic field application (Lee et al, 2022b).…”