SBIR Phase II: Ultrasonic Nanocoining for Creating Large, Low-Cost Arrays of Sub-Wavelength Features

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase II project will be in development of Ultrasonic Nanocoining - a new platform technology that is used to generate plastic films or glass panels that are anti-reflective, self-cleaning, or colored through structure. Such nano-structured surfaces can provide benefits for a wide array of commercial applications, ranging from consumer electronics to automotive and aerospace. These surfaces can save energy by preventing internal reflections in OLED displays and cover-glass reflections on the surface of solar panels. What?s more, these surfaces enable better use of available space by adding functionality to surfaces without adding any appreciable volume. Nanocoining is a low-temperature, chemical-free process that does not rely on chemical etching or nano-particles, which have recently come under scrutiny from the EPA because of unknown health and environment effects. The science contained within the project spans several disciplines, and Nanocoining would ultimately contribute to low-cost, scalable manufacturing for a wide array of industries. Ultrasonic Nanocoining enables low-cost, high volume reproduction of surface textures comprised of nano-structures that are smaller than the wavelength of visible light. This is done by creating a cylindrical mold with a nano-structured surface, then imprinting that mold into plastics using roll-to-roll processing. The objectives of the current project are to use Nanocoining to indent billions of sub-wavelength features into both flat and cylindrical Nickel-plated molds in a continuous pattern, then use these molds to replicate the structure into a variety of polymer materials using roll-to-roll processing. The research will study each step of the mold fabrication process, including focused ion beam machining of the diamond die, controlling a dual-mode ultrasonic resonant actuator and registering millions of indents side-by-side without leaving a significant seam between them. Replicated film surfaces will be tested for optical and wetting properties, and the final result will be functionalized transparent film samples that prove commercial potential. In the future the process may be used to create meter-scale nano-structured metal molds for production-scale imprinting.