August 1, 2015.
Low energy surfaces can strongly repel both oil and water. Recently these surfaces have been fabricated on various substrates including fabric, aluminum, stainless steel and many other materials. In this experiment we explore the use of low energy surface deposition on aluminum alloy, stainless steel and silicon substrates, to enhance the drying rate of liquids removed from the surface by forced convection. We control surface roughness by substrate abrasion and by the growth of Al2O3 nanograss to enhance liquid repellence by use of a hierarchical texture. Liquid repellence of the substrates is measured by contact angles of the probe liquids, water and hexadecane. Samples are mounted on a rigid stage constructed with a flat surface and a regulated air nozzle fixed to provide flow parallel to the substrate surface. s. It is shown that drops on omniphobic and superomniphobic surfaces move at increased velocity compared to untreated surfaces, and leave behind less residual liquid, resulting in a faster drying rate. A two-factor design of experiments (DOE) was implemented to explore the optimum conditions for a fast drying low energy surface. The application of this work can be used in rocket engines, rooftops, cars, umbrellas, tiles, oven, paint, or any kind of fabrics.
Analytical Chemistry | Engineering Education | Materials Chemistry | Mechanics of Materials | Nanoscience and Nanotechnology | Other Chemistry | Physical Chemistry
Jeffrey Alston and Andrew Guenthner
Air Force Research Laboratory (AFRL)
This material is based upon work supported by the National Science Foundation under Grant No. 1340110 and is made possible with contributions from the S.D. Bechtel Jr. Foundation, Howard Hughes Medical Institute, Chevron Corporation, National Marine Sanctuary Foundation, and from the host research center. Any opinions, findings, and conclusions or recommendations expressed in this material are solely those of the authors. The STAR Program is administered by the Cal Poly Center for Excellence in STEM Education on behalf of the California State University system.
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