Standing Enokitake-like Nanowire Films for Highly Stretchable Elastronics

Abstract

Stretchable electronics may enable electronic components to be part of our organs-ideal for future wearable/implantable biodiagnostic systems. One of key challenges is failure of the soft/rigid material interface due to mismatching Young's moduli, which limits stretchability and durability of current systems. Here, we show that standing enokitake-like gold-nanowire-based films chemically bonded to an elastomer can be stretched up to 900% and are highly durable, with >93% conductivity recovery even after 2000 stretching/releasing cycles to 800% strain. Both experimental and modeling reveal that this superior elastic property originates from standing enokitake-like nanowire film structures. The closely packed nanoparticle layer sticks to the top of the nanowires, which easily cracks under strain, whereas the bottom part of the nanowires is compliant with substrate deformation. This leads to tiny V-shaped cracks with a maintained electron transport pathway rather than large U-shaped cracks that are frequently observed for conventional metal films. We further show that our standing nanowire films can serve as current collectors in supercapacitors and second skin-like smart masks for facial expression detection.

Intrinsically Stretchable Fuel Cell Based on Enokitake‐Like Standing Gold Nanowires

“…[33][34][35] As was shown in our recent report, [37] we demonstrated that the v-AuNWs could be used to design microsupercapacitors with discriminative capacitance depending which side was exposed. [33][34][35] As was shown in our recent report, [37] we demonstrated that the v-AuNWs could be used to design microsupercapacitors with discriminative capacitance depending which side was exposed.…”

“…From the cross section view of the v-AuNWs based electrode ( Figure S1C, Supporting Information), it was further confirmed the enokitake-like structure and orientation of the v-AuNWs with their length and diameter to be about 3.5 µm and 12.8 nm, respectively. [32][33][34] The two as-prepared types of stretchable electrodes were first pre-treated in H 2 SO 4 solution to obtain clean surfaces for the electro-oxidation application ( Figure S1D, Supporting Information). [32][33][34] The two as-prepared types of stretchable electrodes were first pre-treated in H 2 SO 4 solution to obtain clean surfaces for the electro-oxidation application ( Figure S1D, Supporting Information).…”

A Wearable Second Skin‐Like Multifunctional Supercapacitor with Vertical Gold Nanowires and Electrochromic Polyaniline

“…[43,44] In brief, the substrate was treated with air plasma for 5 min to improve its surface hydrophilicity before immersed in APTES ethanol solution for 1-2 h to functionalize its surface with amino groups. [43,44] In brief, the substrate was treated with air plasma for 5 min to improve its surface hydrophilicity before immersed in APTES ethanol solution for 1-2 h to functionalize its surface with amino groups.…”

“…[38][39][40][41] Here, we report on a wearable second skin-like multifunctional supercapacitor with self-assembled vertical gold nanowires (v-AuNWs) and electrochromic PANI. In comparison to traditional synthesis of gold-based conductive film such as evaporation, sputtering, or other gilding methods, [42] v-AuNW films offer the advantages of high softness and stretchability that retain integrity under severe deformations, firm attachment to the substrates with high electroactive surface area [43,44] -the two key requirements for current collectors in skin-like ultrathin supercapacitors. Furthermore, the growth of v-AuNWs is entirely solution-based, enabling conformal and cohesive coating on virtually any soft elastomeric or hard substrates with various complex surface morphology.…”

“…Furthermore, the growth of v-AuNWs is entirely solution-based, enabling conformal and cohesive coating on virtually any soft elastomeric or hard substrates with various complex surface morphology. [43,44] The detailed preparation procedures are illustrated in Figure S1 in the Supporting Information and described in the Experimental Section. We also show that the multifunctional supercapacitors could be patterned into conformal "tattoo-like" patches on soft dynamic human skin.…”