I wish they hadn't used "physics-defying" in their press release because I'm certain this is an important discovery for water condensers, but claiming it doesn't need an external energy source is massively negligent.
I'm fairly certain they've created some form of a Brownian Ratchet: https://en.wikipedia.org/wiki/Brownian_ratchet
People love to claim there's no external energy source, but then when you look closely, you'll find a hot-cold differential, and then you need external energy to maintain that differential. I'd put a large sum of money that either the material is colder than the ambient environment or the incoming moisture is warmer than the ambient environment. It might even be a differential within their material, and the lab lights are warming one side! There's a lot of passive devices that rely on the hot-cold cycle of day and night, that still counts as energy input from the sun.
The article even mentions they tried to rule out a thermal gradient by increasing the thickness of the material, I'm not sure I understand why that would rule it out... the gradient would still exist.
I hate this, because if they aren't intentionally supplying energy, it's probably really efficient (assuming they aren't taking samples out of the freezer or something) so it's still a big deal and important but apparently we have to claim something is a perpetual motion machine to get attention among the public.
Yeah I understand the need for an university to make the news once in a while, and the fact that this made the front page here proves the effectiveness of the method, but the terms "Passively Harvest" and "Defies Physics" should be used very carefully in the context of a scientific publication, even though it's only a blog post so we don't expect peer-reviewed journal levels of rigor.
I feel that it disserves science in the end, the belief that some magic material is going to break the second law of thermodynamics is closer to alchemy than chemistry.
PET is a decent insulator, and they seem to be trying to ensure it wasn’t the temperature difference causing condensation, but the nano structure itself. I’m assuming they were controlling temperature and humidity, so it would mean the material must get hotter, but that seems like it can also be passively solved with a radiator. What they are describing would be a pretty big deal and seems plausible.