How can all three of these liquids be rooted in the same science? The key is in the molecule. A molecule’s identity has to do with its character – a character that defines its many properties.
Take physical properties, for instance. They are largely governed by intermolecular forces, or forces of attraction that exist between one molecule and another molecule. Intermolecular forces are important because their strength explains how physical properties, like boiling point, can have a powerful impact on a liquid.
When does a liquid boil? When its molecules have enough energy to break free of the attractions between those molecules.
With this knowledge in mind, 3M scientists went to the lab to create phase-shifting fluids that have the ability to do vastly different things, like clean, cool and protect, with slight changes in their boiling points.
They’re called 3M™ Novec™ fluids.
Novec compounds combine certain properties, like non-flammability and low toxicity, all into a family of molecules.
“All of the pure Novec fluids have different boiling points due to their different chemical structures and molecular weights,” says John Owens, who is a lead research specialist working with 3M’s Novec fluids.
“This range of boiling points was created in order to optimize the performance of the fluids in different applications. Some applications require higher volatility with a material that evaporates more quickly. For these applications, we would select a fluid with a lower boiling point,” says John. “Other applications require transferring heat at relatively high temperatures. For those applications, we developed the fluids with higher boiling points so that this could be accomplished at reasonable working pressures.”
Because of this, many industries like aerospace, electronics and health care rely on Novec fluids to clean and Novec coatings to help protect devices. Libraries and museums use it to help preserve national treasures. The Smithsonian Institution National Museum of Natural History even uses it to help preserve the world’s largest squid specimen. The Library of Congress, the nation’s oldest federal cultural institution, is among the list of places using a Novec fluid to help protect documents from fire risks.
So, what does it take to create molecules with this many characteristics and uses?
3M scientists and engineers from across the globe collaborated to create what is now the broadest category of Novec fluids: segregated hydrofluoroethers (HFEs) – basically, a molecule with a fluorocarbon on one side and a hydrocarbon on the other side, connected by an oxygen atom (the ether).
It’s this chemical makeup that allows Novec fluids to comply with current ozone-protecting and global-warming regulations – revealing the very impetus for why Novec solutions were created.
The scientists put these atoms together in a way that would help solve some environmental challenges that were gaining attention in the early ‘90s.
“People were looking for replacements for chemicals that were ozone-depleting substances,” says John.
That’s because the ozone-depleting substances contained chlorofluorocarbons (CFCs), which were the cleaning medium of choice at the time – but, environmental regulations caused these solvents to begin being phased out in the mid-1990s because of their high ozone-depletion potential (ODP).
The solution? Scientists looked to create a solvent that could perform similarly to CFCs, but without creating environmental issues in its use.
“While we were trying to replace an ozone-depleting chemical, we wanted to make sure it didn’t contribute to some other environmental concern or create a safety risk,” says John.
So, scientists set out to invent materials that had zero ozone depletion-potential, but also looked ahead to create materials designed to be low in global-warming potential, with low greenhouse gas emissions.
Since the ‘90s, a new need has emerged: in data centers – where the amount of data carried is on the rise.
“We see that trend continuing, and it is creating a burden on the grid in terms of the electricity and space required by the servers,” says Jim Ehle, who is a business manager for Novec fluids at 3M.
The data centers consume a lot of energy, and because there is a great amount of heat generated through the operation of the computers, cooling is critical to both performance and energy efficiency.
The current solution is to air-cool the servers, but this solution can require a lot of energy to cool and flow the air across the server. It can also be corrosive to servers in places where air pollution is high. Companies, like 3M, are making headway in finding other solutions – like developing commercial solutions for liquid immersion cooling.
“You can dramatically reduce this energy use through liquid cooling,” says Jim.
With immersion cooling, the liquid does the cooling passively instead of using additional energy to blow air across the boards. This can result in a much smaller equipment footprint and a significantly smaller environmental footprint.
Immersion cooling allows tighter packing of components, enabling up to 100 kilowatts of computing power per square meter, compared to just 10 kilowatts in a typical air-cooled system. This means the data center could be housed in 10 times less floor space.
There’s another Novec fluid used in data centers, but for a different purpose: fire suppression. The benefit of this fluid is that it doesn’t damage electronics the way a water-based system can.
“In data centers, it’s critical that service isn’t interrupted. If you only have a water sprinkler system during a fire, the sprinkler will go off and damage your equipment,” says Jim. “This will prevent the data center’s business continuity from running efficiently.”
But, the outcome is different with 3M™ Novec™ 1230 Fire Protection Fluid.
“With Novec 1230 fluid, the fire will be extinguished, and the data center can keep running. It is designed to not damage the electronic equipment so you can sustain your operations,” says Jim.
Traditionally, manufacturers use water to clean precision parts – but they have to load the water with things like detergents in order for it to be able to effectively clean through tight spaces. Novec fluid is designed to do the same job, but without any help from detergents.
Imagine if you wanted to get a layer of wax removed from a piece of glass, for instance. If you place the glass into a vapor degreaser that contains Novec fluid, the wax can easily dissolve, even in the vapor phase.
When heated above its boiling point, the Novec fluid is transformed into a gas that is very heavy. It has a density many times that of air, so it just wants to sit down on top of the liquid in the tank.
When immersing parts in the Novec fluid inside the vapor degreaser, you’ll see tiny implosions appearing within the fluid through a process called ultrasonication, where sound energy is used to agitate particles in a sample.
“A sonic transducer cycles 40,000 times a second and creates little bubbles inside the fluid. As those bubbles pop, they provide mechanical agitation to the part, removing the wax,” says Karl Manske, a technical service specialist who works in the lab with Novec fluids at 3M.
But, that doesn’t happen without help from the Novec fluid, which will transform from a liquid phase to a vapor phase. This transformation allows the Novec fluid to gain the power it needs to immediately condense onto the glass, allowing the wax to melt and dissolve off the glass.
“For parts that have a lot of intricate architecture with blind holes or tight spaces where you have to clean in between spaces, the Novec fluid will wet in between all these areas,” says Karl.
If you want to keep wetness out of areas, Novec coatings can also be a surprising solution.
For instance, disguised within some smartphones, you may find a Novec coating on one of your phone’s most important components: the circuit board. Novec electronic grade coatings provide a fluorinated polymer barrier to water and corrosion on circuit boards.
This is especially helpful since we all want to avoid circuit board shorts caused to our phones by water and moisture exposure.
The effectiveness of the coating has to do with surface tension. The Novec fluids that the coatings are delivered from have a low surface tension. “We dissolve into the Novec solvent a fluorinated polymer coating. This low viscosity, low surface-tension coating solution gets in and around all components on a circuit board, depositing a layer of Novec coating providing good coverage,” says 3M chemist Greg Marszalek.
We compared an uncoated glass microscope slide dipped in water to a glass microscope slide dipped in a Novec electronic grade coating.
See how a drop of water reacts to both slides.
On the uncoated glass, you’ll notice how the water goes right underneath the glass. But, on the coated glass, you’ll see how the water beads up and doesn’t go underneath the glass.
“The coating adds a hydrophobic barrier, so if you get water or moisture on your board, the water will just run off,” says Greg.
Watch an experiment showing the hydrophobic nature of a Novec electronic grade coating.
Scientists have their eyes set on making the grid even greener.
“Where we once replaced materials that were ozone-depleting or flammable or had concerns over toxicity, we’re now replacing materials that are potent greenhouse gases,” says John.
That means creating solutions that are more effective than their alternatives, like sulfur hexafluoride (SF6) – a relatively high-pressure gas used in protecting high-voltage power equipment down on the electric grid. It’s found in transformers, switch gears and circuit breakers. “All these pieces of equipment are filled with SF6,” says John. “The industry knows they need to replace that material, because it’s the most potent greenhouse gas ever identified.”
One solution? “We’re able to use low-pressure fluorinated gases mixed with more common gases, like dry air or carbon dioxide, to successfully replace the sulfur hexafluoride,” explains John.
There’s also a lot of excitement around the electric car revolution. One big industry goal is to improve the batteries of electric vehicles (EV) by enhancing the performance of EVs through thermal management of the EV battery. “Novec fluids are being evaluated for managing the temperature of the EV batteries, and by doing so, may extend battery cell life and allow faster charge and discharge times,” says Jim.
And one day, Novec fluids may allow the worlds of data centers and driverless vehicles to intersect. One of the new applications for high-density data centers will be driverless vehicles.
“There will be massive amounts of data going between the data center and autonomous vehicles,” says Jim. “We think those data centers will need to be liquid-immersion cooled. Air cooling won’t be sufficient because the amount of data being transmitted will cause an electrical and space burden on the grid.”
John has seen Novec fluids through their entire journey, and is excited for the future.
“Originally, we didn’t immediately get to these molecules. There was a lot of testing. There were a number of materials that weren’t successful,” he says. “You often learn just as much from the things that fail as you do from the things that do have success. You learn what to do next.”