Spider silk-inspired universal strategy: Directional patching of one-dimensional nanomaterial-based flexible transparent electrodes for smart flexible electronics

With high figure of merits (FOMs) and intelligent responsiveness, flexible transparent electrodes (FTEs) based on one-dimensional nanomaterials (1DNMs), covering silver nanowires (AgNWs), copper nanowires (CuNWs) and carbon nanotubes (CNTs), are of great promise for smart flexible electronics. Inspired by directional collection of water droplets on wetted spider silks, we propose a universal strategy applicable to AgNW-based FTEs, CuNW-based FTEs and CNT-based FTEs. That is, the 1DNM-based FTEs are wetted by patch precursor mist and then, due to a synergism of surface energy gradient (making the 1DNMs preferentially capture patch precursor microdroplets) and anisotropic fast volatilization (producing a driving force for power-free micro-droplet transport), are directionally patched in a mild way (ultraviolet-triggering). The directional formation of flexible conductive patches at the junctions of 1DNMs can significantly lower and stabilize the contact resistance of 1DNM-1DNM, and thus both high electri-optical and electri-mechanical FOMs of 1DNM-based FTEs are achieved. Moreover, because of the switchability of conducting polypyrrole (PPy) in the patches, the patched FTEs have a switching behavior of electrical conductivity in response to periodic electrical stimuli. Upon the electrical switch, the smart flexible electronic devices integrated with patched 1DNM-based FTEs are proved to be of practicability and reliability. The bioinspired universal strategy opens up a new avenue to achieve high FOMs of 1DNM-based FTEs of potential use in smart flexible electronics. This study also offers an attractive approach for directional repair or reconstruction of 1DNMs, as well as for precise intelligentization on solid surfaces or interfaces.