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posted by cmn32480 on Wednesday August 19 2015, @06:02PM   Printer-friendly
from the not-your-mama's-surface-texture dept.

Science Daily has an interesting article which focuses on a new understanding of how surfaces deflect water and the engineering of correct surface roughness to trap the vapor that provides dryness when submerged.

Understanding how the surfaces deflect water so well means the valuable feature could be reproduced in other materials on a mass scale, potentially saving billions of dollars in a variety of industries, from antifouling surfaces for shipping to pipe coatings resulting in lower drag.

The research team is the first to identify the ideal "roughness" needed in the texture of a surface to keep it dry for a long period of time when submerged in water. The valleys in the surface roughness typically need to be less than one micron in width.

Samples with the nanoscale roughness remained dry for up to four months, the duration of the experiment. Other samples were placed in harsh environments, where dissolved gas was removed from the ambient liquid, and they also remained dry.

Historically, scientists had not understood how to keep water vapor from succumbing to condensation within the pore, which can cause water to wet the surface. But the Northwestern team found the molecular key: They demonstrated that when the valleys are less than one micron in width, they can sustain the trapped air as well as vapor in their gasified states, strengthening the seal that thwarts wetness.


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  • (Score: 2) by jimshatt on Wednesday August 19 2015, @06:21PM

    by jimshatt (978) on Wednesday August 19 2015, @06:21PM (#225110) Journal
    I wonder if small organisms like bacteria are able to disrupt the surface tension of the water, making it harder to remain dry. Maybe they tested with sterilized surfaces or it just isn't significant.
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  • (Score: 1) by captain_nifty on Wednesday August 19 2015, @07:21PM

    by captain_nifty (4252) on Wednesday August 19 2015, @07:21PM (#225135)

    I would be more concerned about Macro-organisms, sea life fouling is pretty nasty stuff, and I don't think a thin layer of gas would do much to stop it in a real world environment.

    Still a pretty interesting technique, it just needs some study into how those micro-channels respond to harsher environments with fouling material and fluid flows, their harsh environment test sounds like a glass of de-ionized water on a shelf.

    I could see uses for this in controlled environments, but I doubt it would do well outside the lab/clean room environment.

    • (Score: 2) by bob_super on Thursday August 20 2015, @12:12AM

      by bob_super (1357) on Thursday August 20 2015, @12:12AM (#225221)

      On the other hand, the micro-organisms that foul wet surfaces grow because there is water there. If there is a permanent airgap, it's not trivial to jump out of the water to attach to the other side.

      But... debris in the water will bridge that gap all the time (Garbage Patch anyone?), displacing, fouling, and quickly rendering the whole thing useless