Geeking Science: Hydrophobic

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Have you ever considered the power of water? It’s enough to make one hydrophobic.

H2O, with its free ions, can act as an acid or a base. We live on a planet where the molecule can exist as gas, liquid, and solid – sometimes all within inches of each other. Plus it has a weird property of getting larger when changing from liquid to solid instead of condensing. Liquid water molecules glom onto neighbors with both “hands” if no one else is near creating a surface tension few substances can beat. All the while being anywhere from transparent to translucent – meaning light can pass through it in both liquid and solid forms, as well as gas. More about its properties can be found at the USGS Water Science School.

Water is amazing.

Taking all these amazing abilities and combining them is what sends a shiver down my spine. 

“Water finds a way.” Sun Tzu, the Art of War

Water vapor is everywhere. Getting a little cold it become water liquid and slips deep into cracks. The water freezes as the temperature drops even more, say a desert at night, and the crack expands. Water beats rock, every single time, fragmenting those hearty souls which traveled from the center of the earth to the surface. Eventually water will take the rock out like a ninja warrior, quiet and deadly. By crack, or acid, or base. Steel rusts. Clothing rots. Stone crumbles. Water allows us to create but also erases everything we make.

Water is scary.

In humanity’s constant search to improve, we are developing techniques of hydrophobic – making our creations throw off water. You may be familiar with some early examples of this field – polytetrafluoroethylene (telfon), stainless steel, and waxed coats. Telfon’s makes a corrosive resistant surface through its molecular bonds; basically water’s friendly ions can’t break into the carbon-fluorine party and start bonding to the surface – hence the non-stick surface. Similarly the process of making stainless steel alloy keeps water ions at bay and make the steel unrustable – but the nickel and chromium costs a lot more than carbon steel so large amounts aren’t practical. And waxed coats are made from cotton dipped in wax making them practical for working near seashores and on boats.

I remember once being in a car with no floor. Seeing the road rush by under your feet at 50 miles per hour is an experience. Younger readers may not remember cars with holes rusting at the doors and around the wheel beds from the combination of salt and water during the winter. Switching to plastic-based materials not only made the cars lighter, so saving gas in trying to move mass, and safer, steel sheets no longer bend into the human compartment during a crash, but the plastic also makes the car body stay together better in northern climates.

But that is then, what am I geeking about now?

Laser technology, chemical technology, nano technology. Scientists are developing other means to keep water from bullying other materials into rust. Why are we going through all this trouble? What possible results are worth this effort?

The field of hydropobics makes incredible practical items – as we previously seen with cutlery which won’t rust, kitchen pans no longer needing to be scrubbed after every use, car staying intact through winter slush, and clothing not getting soaked when working around water. Can we change the substance property? Should it be an alloy, a coating, or maybe just modifying the shape can make something hydropobic?

You may have already seen one of the recent applications, hydrophobic paint. Some cities have started painting the outside of the first floor of buildings near the bar district. Now let the peeing person beware – draining the drink can bounce back at ya. Cool, right?

Anyone who travels by plane during the winter – when water really shows off its ability to go from liquid to solid and back again – is well familiar with the wait for the deicing preparation of wings. Nasty chemicals are sprayed on the wings.

A new technology of laser technology changes the surface of the metal wings so water surface tension is shrugged off. No liquid water on wings means no ice forming from the liquid as the temperature drops. No deicing steps are needed, ever again – saving time, chemicals, and my holiday schedule. Totally geeking about this application.

Initially they were trying the paint, but that didn’t work. (MIT 2010) Instead a complicated pattern surface was recommended, something like what the University of Rochester has been working on. 

The deicing technology is important for food shipment, electrical wires, the car windshield in winter, sidewalks, as well as the previous mentioned planes.

And who wouldn’t want clothes which won’t stain. Liquid repel right off. Okay, taking water out of the equation will make washing them more difficult, but how often will you need to wash them, really? No sweat, mud, no food stains, no drinks down your back when someone bumps into you by “accident”. Sounds like Science Fiction – but it’s real. Available right now – not truly practical as clothing in price or application as yet unless you are one of those who can live in multi-million dollar homes.

I predict in a decade we will go crazy about this fabric just like we did with wrinkle free polyester in the sixties. It will last for about a year, just like the chainmetal cloth of the eighties. Why? Because one of the most important properties of clothing is wicking moisture (sweat) away from the body in a cooling action. The quote of “Your scientists were so preoccupied with whether they could, they didn’t stop to think if they should.” (Jurassic Park screenwriter) applies to hydrophobic clothing.

On the other hand, gloves able to shrug off concrete and tar and boots able to walk through mud are already an industrial application in use today.

Applications will continue to grow for hydrophobic technology, whether the long-imagined un-iceable plane or the unexpected application against nocturnal urination.

“Water finds a way.”

But humanity is going to make it really, really tough for water to win.

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