Fluidic Control through Surface Engineering

Z. Liu, T.F. Yap, R. Shveda, D. Kahanda, D.J. Preston
Rice University,
United States

Keywords: wettability, wicking, robust, coatings, lubricants, micro/nano

Summary:

Rational design of surfaces, from the macroscale to the molecular scale, enables control over fluidic behavior, including the manipulation of droplets and bubbles. Surface geometry, intrinsic chemical nature, and the interplay between these two design parameters govern fluidic interactions with surfaces. One important application space includes condensers, which are universal within industry. Tuning the surface wettability of a condenser can improve system-level efficiency by several percent, but the appropriate surface modification varies depending on the system. For example, condensation of water within a steam cycle used to generate electricity can be improved over 10x by utilizing a superhydrophobic surface coating, causing droplets to shed from the surface at the microscale. On the other hand, condensation of a refrigerant, as in air conditioning systems, benefits from a surface with a high affinity for the refrigerant, which can improve heat transfer rates by up to 400% by forming a thin film that is wicked away from the surface. In our work, surface modifications are performed using scalable approaches that can be translated to industrial applications, with a focus on durability and long-term performance, and an interest in new materials and coatings.