Facile and highly efficient fabrication of robust Ag nanowire–elastomer composite electrodes with tailored electrical properties
The fabrication of Ag nanowire (AgNW) patterns on a working substrate is a critical step to prepare flexible/stretchable electronics. The conventional method of making AgNW patterns is based on a 2-D mask, which suffers some serious drawbacks, such as low material usage, difficulty in preparing complex patterns, and susceptibility to damaged pattern edges. To overcome these drawbacks, this study proposes the use of a 3-D mask, which when combined with a vacuum filtration system, allowed efficient fabrication of complex AgNW patterns with clear edges. In addition, we controlled the microstructure of the patterned AgNW/polydimethylsiloxane (PDMS) electrodes transferred from the membrane filter, obtaining stretchable electrodes with anisotropic electrical properties. Moreover, we greatly improved the stability and reliability of the patterned electrodes in long-term stretch/release tests by developing a PDMS/AgNW/PDMS sandwich structure. Based on these improvements, robust stretchable electrodes with a stretchability of over 80% uniaxial strain and tunable gauge factors ranging from 0.07 to 520 (a much wider range than previously reported) were fabricated by optimizing the AgNW deposition density and PDMS peel-off direction. Finally, we demonstrated the applicability of the proposed method by fabricating stretchable circuits which were able to either maintain a stable resistance or sensitively monitor various human motions, revealing its tremendous potential for applications in flexible/stretchable electronics.