Laser Draw-Casting of Nanowires

wire-websiteMetal nanowires (NW) have demonstrated a wide range of beneficial scale-effects, leading to increased mechanical strength, ductility and multi-functionality. They are typically fabricated through chemical synthesis processes leading to colloidal dispersion having small length (< 100 μm) .

Our goal is to use a top-down approach to draw metal NW having continuous length. We are studying a new process where a commercially available metal wire having > 20 μm diameter is is encapsulated in a silica capillary tube, heated using CO2 laser, and drawn at very high speeds to reduce its diameter to 200 nm. The metal wire melts, and is cast onto the silica capillary tube as it is being drawn. We call the process Laser Draw-Casting (LDC).

Using this process, we fabricated Palladium (Pd) NW having several cm length, and demonstrated their integration in highly stretchable conductors. The wires have bamboo-like high aspect ratio crystal structure, and demonstrate high ductility. This enables them to accommodate plastic buckling on pre-stretched elastomer substrate, and achieve less than 0.5% change in resistance when stretched by up to 800%.