Wearable electronic devices need components that are bendable and stretchable. This can be achieved, for example, with silver nanowires (AgNWs), which are electrically conductive and retain this property when they are deformed. Fully coating a stretchable material with AgNWs to create a conductive film is fairly simple. Creating AgNW patterns for specific applications is more challenging. Existing methods either require expensive equipment, cannot create high-resolution patterns, or have limited substrate scopes.

Wei Yuan, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Fushan Li, Fuzhou University, China, and colleagues have developed a new method for patterning AgNWs that combines two simple techniques: screen printing and vacuum filtration. The team first created a patterned screen stencil. This stencil was then used to screen-print the negative of the pattern onto a poly(tetrafluoroethylene) (PTFE) filter membrane, using liquid poly(dimethylsiloxane) (PDMS) to create an elastic mask. Finally, an AgNW dispersion is vacuum-filtered through the membrane. The nanowires are deposited only on the uncovered area of the membrane not protected by the PDMS, and thus, form the desired pattern.

The resulting AgNW films can be transferred to PDMS surfaces to create stretchable, transparent, patterned conductive films. These films have high optical transparency, low sheet resistance, and good mechanical flexibilitiy. They can, for example, be used as electrodes to create elastic electroluminescent displays.

• Facile and Efficient Patterning Method for Silver Nanowires and Its Application to Stretchable Electroluminescent Displays,
  Yong Lin, Wei Yuan, Chen Ding, Shulin Chen, Wenming Su, Hailong Hu, Zheng Cui, Fushan Li,
  ACS Appl. Mater. Interfaces 2020.
  https://doi.org/10.1021/acsami.9b21755