STAYING DRY, MINISCULE-FASHION

THIS IS A SMALL SIMANAITISSAYS ITEM DESCRIBING really small stuff, nanoparticles that help to keep things dry. The report from A? Aalto University, October 23,  2023, announces, “Revised method to create hydrophobic surfaces has implications for any technology where water meets a solid surface, from optics and microfluidics to cooking.” 

Wikipedia describes, “Aalto University (Finnish: Aalto-yliopisto; Swedish: Aalto-universitetet) is a public research university located in Espoo, Finland. It was established in 2010 as a merger of three major Finnish universities: the Helsinki University of Technology, the Helsinki School of Economics and the University of Art and Design Helsinki. The close collaboration between the scientific, business and arts communities is intended to foster multi-disciplinary education and research.”

And evidently this collaboration is paying off, big time in nano research. I like its logo, especially when expressed A?, a questing for knowledge.

Challenging Existing Ideas. Aalto says, “Researchers have developed a new mechanism to make water droplets slip off surfaces, described in a paper published in Nature Chemistry. The discovery challenges existing ideas about friction between solid surfaces and water and opens up a new avenue for studying droplet slipperiness at the molecular level.”

Self-assembled Monolayers. Aalto continues, “Liquid-like surfaces are a new type of droplet-repellent surface that offer many technical benefits over traditional approaches—a topic recently reviewed in Nature Reviews Chemistry by Aalto University Professor Robin Ras. They have molecular layers that are highly mobile yet covalently tethered to the substrates, giving solid surfaces a liquid-like quality acting like a layer of lubricant between the water droplets and the surface itself.”

Image by Ekaterina Osmekhina from Aalto. 

Researchers work at the nanometer level (billionth of a meter; 0.00000004 inch) studying molecular interactions with these SAMs (“Self-assembled monolayers”). Optimal slipperiness occurs when SAM coverage is high or low, the latter counter to conventional thinking. Doctoral researcher Sakari Lepikko describes, “We found that, instead, water flows freely between the molecules of the SAM at low SAM coverage, sliding off the surface. And when the SAM coverage is high, the water stays on top of the SAM and slides off just as easily. It’s only in between these two states that water adheres to the SAMs and sticks to the surface.”

Anti-fogging, De-icing, Self-cleaning. Aalto notes, “The discovery promises to have implications wherever droplet-repellent surfaces are needed. According to Lepikko, this covers hundreds of examples from daily life to industrial solutions.”

Lepikko says, “Things like heat transfer in pipes, de-icing and anti-fogging are potential uses. It will also help with microfluidics, where tiny droplets need to be moved around smoothly, and with creating self-cleaning surfaces.”

An Earlier Discovery. This reminds me of WD-40, the name standing for Water Displacement, 40th formula. This one, Wikipedia describes, “acts as a lubricant, rust preventive, penetrant and moisture displacer. There are specialized products that perform better than WD-40 in each of these uses, but WD-40’s flexibility has given it fame as a jack of all trades.”

It could well be that Aalto University’s tiny SAMs could benefit everything from aircraft windshields to eyeglasses to medical injections. Quite a potential. ds

© Dennis Simanaitis, SimanaitisSays.com, 2023