Wednesday, February 11, 2015

Nano-tech Experiment #3 (and reports on #1 and #2)

This post originally appeared on Windborne in Puget Sound

This is the third experiment with the Rustoleum nano-tech product called "NeverWet" - a super hydrophobic coating that can be applied from a spray can.  (Experiments #1 and #2 are here and here.)
For this experiment, we will be seeing how long the retained air film persists, and if the nano-coating has any anti-biological properties in sea water.  I think it might, since the retained air film could make barnacles and such uncomfortable, or might even prevent them from touching and attaching to the actual surface.  We'll see. 

Here's what I did:
  • I took a scrap of fiber-reinforced ABS plastic (left over from the refrigerator refurbishment) and masked off one side of it.  The other side got the NeverWet treatment.  I suspended it (from the hole you can see, partially covered with blue tape) in the water off our finger pier at Anacortes on December 21, 2014.  The finger pier is a floating one, so the coupon will never be exposed to air, except when I lift it up for inspection.

Report on Experiment #1

Experiment #1, as of Dec 2014
Experiment #1 began more than a year ago, in October, 2013.  For this test, I applied the NeverWet to our canvas sea hood. All was well until Nature's own nano-tech (pine pollen) arrived on the scene.  It coated and buried the NeverWet, and allowed water to once again wet the surface.  In an attempt to remove the pollen, I gently wiped part of the surface with a sponge damped in soapy water.  As you can see, that portion of the surface never recovered its hydrophobic properties.  Whether it was the mechanical action of the sponge or the surface tension-destroying property of the soap, I will never know.  But the portion of the sea hood that did not suffer from pollen accumulation or the soapy sponge is still every bit as water-repellent as ever.  From this I can propose that the coating is not strongly affected by UV.

Report on Experiment #2

Experiment #2 began in April of 2014, when I applied NeverWet to our dinghy propeller. It was amazing to see that the submerged prop looked like it was made of polished silver due to the thin layer of air it retained while submerged.

We used the dinghy normally for the entire 2014 season, giving no further thought or special attention to the prop.

By the end of the season, the nano-tech coating had ablated off the outer 1/2 of the propeller blades, but was still active on the inner half.

From this I conclude that NeverWet is not suitable as an anti-barnacle coating for boat props (guess we're still stuck with Barnacle Ban), but it could likely serve well on things that do not suffer from the abrasion of high-speed turbulent water contact.

The Future

It is the results of Experiment #2 that led to Experiment #3. Experiment #2 showed that the air film persisted while submerged over periods of days, and even in the presence of extreme turbulence. Will it be retained for months on end? And if indeed the retained air film is effective at retarding or preventing biological growth, NeverWet could serve for difficult-to-protect items such as depth sounder or speedo transducers.  And if the price could be gotten down low enough, perhaps NeverWet could even serve as a bottom paint alternative (for sailboats at least).

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