Mechanically-gated electrochemical ionic channels with chemically modified vertically aligned gold nanowires.

ABSTRACT

Mechanically-gated ion channels play an important role in the human body, whereas it is challenging to design artificial mechanically-controlled ionic transport devices as the intrinsically rigidity of traditional electrodes. Here, we report on a mechanically-gated electrochemical channel by virtue of vertically aligned gold nanowires (v-AuNWs) as 3D stretchable electrodes. By surface modification with a self-assembled 1-Dodecanethiol monolayer, the v-AuNWs become hydrophobic and inaccessible to hydrated redox species (e.g., Fe ( CN ) 6 3 - / 4 - and Ru ( bpy ) 3 2 + ). Under mechanical strains, the closely-packed v-AuNWs unzip/crack to generate ionic channels to enable redox reactions, giving rise to increases in Faradaic currents. The redox current increases with the strain level until it reaches a certain threshold value, and then decreases as the strain-induced conductivity decreases. The good reversible "on-off" behaviors for multiple cycles were also demonstrated. The results presented demonstrate a new strategy to control redox reactions simply by tensile strain, indicating the potential applications in future soft smart mechanotransduction devices.