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

Abstract

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 μm), highly conductive (up to 1.26 × 10 5 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.

Hierarchically Ordered Grid-Type Silver Nanowire Microelectrodes via Direct Ink Writing

“…The fabrication of square HO AgNW grids, as shown in Figure 1a, is similar to that in our previous report. 12 Briefly, aqueous AgNWs ink was deposited onto the PET substrate by employing a DIW technique. The line width and pitch of the grids can be modulated well by controlling the DIW parameters.…”

Emerging Additive Manufacturing Methods for Wearable Sensors: Opportunities to Expand Access to Personalized Health Monitoring

“…Resolution limitations remain a key challenge for DIWbased printers arising from materials deposition and form holding constraints. [146,147] Recent examples demonstrate the use of optimized ink formulations to obtain printed soft electrodes [148] and piezoresistive sensors [128] with feature sizes on the order of 50 𝜇m. Emerging DIW techniques, such as freeform reversible embedding of suspended hydrogels (FRESH), [149,150] can further enhance printer resolution or expand material compatibility.…”

Wet Film Leveling for Promoting the Uniformity and Conductivity of Silver Nanowire Transparent Electrode

“…As the base of flexible electronics, a silver nanowire (AgNW) transparent electrode has broad application prospects. − For practical application, the uniformity of the transparent electrode is important. To promote the uniformity of AgNW transparent electrode, researchers have developed many excellent strategies. − First, researchers improve the wettability between the ink and the substrate. , Specific methods include adjusting the surface tension of the ink and substrate by the following methods: ozone activation, corona treatment, binder coating, adding surfactant or low-surface-tension material, etc. − Second, the drying process is carefully controlled to relieve the problem of coffee ring and punctate film. − Third, the film-preparation technology (ink dosage, coating speed, etc.) is optimized. , Through these strategies, the uniformity of the AgNW transparent electrode is greatly improved.…”

“…7−10 First, researchers improve the wettability between the ink and the substrate. 11,12 Specific methods include adjusting the surface tension of the ink and substrate by the following methods: ozone activation, corona treatment, binder coating, adding surfactant or low-surface-tension material, etc. 13−15 Second, the drying process is carefully controlled to relieve the problem of coffee ring and punctate film.…”