(274j) Enhanced Fog Water Collection from Wire Mesh Structures

Authors: 
Kleingartner, J. A., Massachusetts Institute of Technology
Cohen, R. E., Massachusetts Institute of Technology
McKinley, G. H., Massachusetts Institute of Technology

Water scarcity is a growing problem in the world today and fog represents an untapped source of water in arid, coastal regions. Plants and animals in these environments have evolved to use chemical and textural features on their surfaces to harvest this necessary resource. In this work, we examine the role of surface wettability and substrate geometry on the overall fog collection efficiency of woven and vertical wire mesh networks. An aerosolized water stream was directed at these meshes in a controlled environment to measure their fog collection efficiency. We utilized a blend of poly(ethyl methacrylate) and a low surface energy molecule (fluorodecyl POSS) to tune the surface wettability of the fog collecting meshes, so that they exhibited low contact angle hysteresis with appreciable surface adhesion, which led to enhanced fog collection efficiency. Low contact angle hysteresis improves drainage of captured water off of the mesh structures and high adhesion decreases the propensity of the captured droplets to be re-entrained in the effluent fog stream. We also extend a previously developed framework for predicting the collection efficiency of mesh based fog collectors. The results of preliminary pilot-scale field experiments using these design elements will also be described.