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)3−/4−6Fe(CN)63-/4-<math> <mrow> <msubsup><mrow><mtext>Fe</mtext> <mrow><mo>(</mo> <mtext>CN</mtext> <mo>)</mo></mrow> </mrow> <mn>6</mn> <mrow><mrow><mn>3</mn> <mo>-</mo></mrow> <mo>/</mo> <mrow><mn>4</mn> <mo>-</mo></mrow> </mrow> </msubsup> </mrow> </math> and Ru(bpy)2+3Ru(bpy)32+<math> <mrow> <msubsup><mrow><mtext>Ru</mtext> <mrow><mo>(</mo> <mtext>bpy</mtext> <mo>)</mo></mrow> </mrow> <mn>3</mn> <mrow><mn>2</mn> <mo>+</mo></mrow> </msubsup> </mrow> </math> ). 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.