Direct Writing of Silver Nanowire Patterns with Line Width down to 50 μm and Ultrahigh Conductivity

Direct writing of one-dimensional nanomaterials with large aspect ratios into customized, highly conductive, and high-resolution patterns is a challenging task. In this work, thin silver nanowires (AgNWs) with a length-to-diameter ratio of 730 are employed as a representative example to demonstrate a potent direct ink writing (DIW) strategy, in which aqueous inks using a natural polymer, sodium alginate, as the thickening agent can be easily patterned with arbitrary geometries and controllable structural features on a variety of planar substrates. With the aid of a quick spray-and-dry postprinting treatment at room temperature, the electrical conductivity and substrate adhesion of the written AgNWs-patterns improve simultaneously. This simple, environment benign, and low-temperature DIW strategy is effective for depositing AgNWs into patterns that are high-resolution (with line width down to 50 mu m), highly conductive (up to 1.26 x 105 S/ cm), and mechanically robust and have a large alignment order of NWs, regardless of the substrate's hardness, smoothness, and hydrophilicity. Soft electroadhesion grippers utilizing as-manufactured interdigitated AgNWs-electrodes exhibit an increased shear adhesion force of up to 15.5 kPa at a driving voltage of 3 kV, indicating the strategy is very promising for the decentralized and customized manufacturing of soft electrodes for future soft electronics and robotics.

Automated summary

This study demonstrates a powerful direct ink writing (DIW) strategy using thin silver nanowires (AgNWs) as a representative example. Aqueous inks with sodium alginate as the thickening agent can be easily patterned with desired geometries and controllable features on various planar substrates. A postprinting treatment at room temperature further enhances the electrical conductivity and substrate adhesion of the written AgNWs-patterns. This environmentally friendly and low-temperature DIW strategy allows for high-resolution, highly conductive, mechanically robust, and well-aligned AgNWs patterns regardless of the substrate's properties.