This project will establish the scientific and technological foundations for texture ratchets as a microfluidic platform for low-cost, parallel handling of droplets. Since their invention in the PI?s lab, we have shown that texture ratchets can perform the essential tasks of droplet generation, transport, splitting, merging, mixing and sorting, all without electric fields, pressure gradients or pumps. We hypothesize that we can extract a wealth of information by observing the dynamics of texture ratchets, starting from the phase lag of droplet oscillation to the intricate motion of the solid-liquid-vapor line along the droplet footprint. The impact of this research will span from a deeper understanding of the physical interactions between liquids and nano-structured surfaces to diagnostics on novel portable devices. Intellectual Merits: Despite decades of research in wetting phenomena and microfluidics, recently there have been dramatic new insights from interdisciplinary efforts by physicists, nanofabrication engineers and developers of biomedical instruments. This project will establish a comprehensive model of texture ratchets and validate it on newly designed devices. Specifically, we will explore texture ratchets as a low-cost microfluidic platform and develop applications for the biomedical arena. Broader Impact: This research sheds light on the behavior of water at the micro- and nano-scale that is relevant well beyond surface physics and nanofabrication, with applications from self-cleaning surfaces to desalination systems. The PI will be involved in activities to connect advanced research to a wider audience: Within UW, he helps establishing an interdisciplinary ?Undergraduate Minor in Nanoscience and Molecular Engineering.? Beyond UW, he hosts classes from North Seattle Community College in UW cleanrooms, participates in MESA outreach programs for K-12 underrepresented minorities, and gives hands-on demos at the Pacific Science Center.
