Kenneth O’Connor has worked with NASA Goddard engineers to develop a nanotextured coating with hydrophobic properties. The technology minimizes dust, liquid, and ice accumulation on its surface, similar to a leaf on the lotus plant. See below for details on a live webinar this month.
NASA Tech Briefs: In what scenarios is this kind of dust removal required?
Kenneth O’Connor: The dust removal part of it is targeting mostly planetary or lunar missions. Dust presents a lot of problems for lunar missions. Lunar dust is very sharp – on the Apollo missions, we saw abrasive damage to the spacecraft and the astronauts’ suits. We also see an impact to the efficiency of solar panels.
NTB: How is the coating designed to remove the dust and the liquid?
O’Connor: Essentially we’ve created a nanotextured surface that has a really low surface energy. Dust sticks to a surface because of van der Waals forces. You’re just giving the dust particles less area to grab on to and also less surface energy to attach to.
NTB: How is the lotus-leaf nature of the design effective?
O’Connor: The reason that a lotus leaf is hydrophobic is for similar reasons. It’s a nano texture that also has a very low surface energy. The coating is modeled after that idea.
NTB: What were your biggest technical challenges when designing this?
O’Connor: We started out working with a university and the company nGimat Corporation. Initially, the coating required a 450 °C bakeout as one of the steps. One of the major challenges that we’ve already dealt with is getting [the coating] into a reasonable temperature application that can be sprayed, or dip- or spin-coated.
NTB: What is the coating designed to withstand?
O’Connor: We haven’t done a lot of environmental testing, but we know that it can [handle] 100 °C in vacuum for a duration. "Vacuum stable" means that the material doesn't degrade when exposed to a vacuum. This is important because we need the material properties. It is also important because we don't want to be a contamination source for the rest of the spacecraft that we are trying to protect. It isn't helpful if we keep a solar cell clean, but generate molecular contaminant in the process.
NTB: What kinds of applications do you envision for the technology?
O’Connor: Certainly, ground-based solar panel systems could benefit from a dust prevention system, because ground-based solar panel systems are sort of at the mercy of dust storms, with dust depositing on your surface.
There are a lot of places where the hydrophobic properties are valuable. If you could get [the coating] cheap enough and durable enough, it would be a great thing to put on your car, and you wouldn’t need windshield wipers. There’s also a need in industry for having temperature detectors that are underwater and may be susceptible to water damage. If you were able to coat those with a hydrophobic surface, then it would be protected. In industry, there are a lot more uses for water [removal]. For anything with corrosion, or anywhere that water is a problem for a process, it can be mitigated with a hydrophobic coating.
To learn more, read a full transcript, or listen to a downloadable podcast, visit www.techbriefs.com/podcast.