Continuous Draw Spinning of Extra-Long Silver Submicron Fibers with Micrometer Patterning Capability

Abstract

Ultrathin metal fibers can serve as highly conducting and flexible current and heat transport channels, which are essential for numerous applications ranging from flexible electronics to energy conversion. Although industrial production of metal fibers with diameters of down to 2 μm is feasible, continuous production of high-quality and low-cost nanoscale metal wires is still challenging. Herein, we report the continuous draw spinning of highly conductive silver submicron fibers with the minimum diameter of ∼200 nm and length of more than kilometers. We obtained individual AgNO/polymer fibers by continuous drawing from an aqueous solution at a speed of up to 8 m/s. With subsequent heat treatment, freestanding Ag submicron fibers with high mechanical flexibility and electric conductivity have been obtained. Woven mats of aligned Ag submicron fibers were used as transparent electrodes with high flexibility and high performance with sheet resistance of 7 Ω sq at a transparency of 96%. Continuous draw spinning opened new avenues for scalable, flexible, and ultralow-cost fabrication of extra-long conductive ultrathin metal fibers.

Aligned Silver Nanowires Enabled Highly Stretchable and Transparent Electrodes with Unusual Conductive Property

“…Some strategies such as rubbing, external field–assisted assembly, coassembly, bubble blowing, dip coating, printing, chemical bonding, strain‐release assembly, wrinkle‐assisted assembly, shear coating, and interface‐mediated assembly can lead to a single oriented layer. And some strategies including Langmuir–Blodgett technique, evaporation‐induced assembly, electrospinning, fluidic flow, spray coating, and brush coating can be repeated to form multilayered oriented structures. However, there are still some inherent limitations that severely restrict their applications as some of the above techniques require complicated process or specialized equipment such as additional transfer process, surface patterning, spraying nozzles, and special substrates, which limit the cost‐effective assembly of high‐density nanowires in a controlled manner.…”

Large‐Scale Direct‐Writing of Aligned Nanofibers for Flexible Electronics

“…So far, only very few approaches can achieve high‐throughput preparation of high‐quality, orderly aligned metal nanowires, meanwhile the pitch gaps are commonly above 100 µm as the limited motion accuracy of the motorized translation stage. Fortunately, Bai et al proposed a continuous draw spinning method to fabricate extra‐long (in kilometers range) silver sub‐micrometer fibers with the minimum diameter of around 200 nm from AgNO 3 /PVP composite precursors, combined with a subsequent heat treatment (250 °C, 2 h) as shown in Figure a. This approach enabled the high‐throughput (≈8 m s −1 ) production of consecutive silver nanofibers, and the formation of uniform arrays with a pitch of down to 5 µm as shown in Figure d.…”

“…f) The relationship between shear stress/diameter and rotational speed of substrate. Reproduced with permission . Copyright 2017, American Chemical Society.…”

Scalable Fabrication of Metallic Nanofiber Network via Templated Electrodeposition for Flexible Electronics

“…One strategy is first to obtain a metal precursor‐containing polymer nanofiber network through an electrospinning or spinning process. Then, the polymer nanofibers are metalized by various treatments, such as thermal annealing, ultraviolet (UV) exposure, and the chemical reduction of metal oxide . The second one is first to obtain a free‐standing polymer nanofiber network by electrospinning.…”