Kerry MacKay takes a look at the technology underpinning waterproof tech, and how science borrows from nature for the next generation of dive suits
ENVIRONMENT
Biomimicry on a blue planet
Kerry MacKay takes a look at the technology underpinning waterproof tech, and how science borrows from nature for the next generation of dive suits
After researching drysuit fabrics and waterproofing for previous columns( see SCUBA issues April and November 2024, and Jan / Feb 2025), I got to wondering what the future of dive fabrics could look like. Is there a sustainable option on the horizon? Could we ever have breathable drysuits to end the‘ boil in the bag’ days?
Almost all of our fantastic technological creations and innovative designs are thanks to nature. Time and again, designers have taken their inspiration from the things they see around them. We have a lot to thank nature for and plenty more to learn.
Thanks to nature, we have more hydrodynamic bionic fins inspired by the movements of marine creatures. Better insulated wetsuits inspired by beaver fur. Heck, even the simple idea of humans breathing underwater was probably inspired by our jealousy of marine creatures.
Before we had synthetic waterproof fabrics, waxed cotton was about as practical as it got. Rubber was a more waterproof option but had poor breathability, so it tended to be used for things like welly boots. In fact, some of the very first drysuits were made from heavy-duty canvas with a rubber coating.
Nowadays, waterproof fabrics are primarily made from synthetic materials such as nylon or polyester. They have a dense weave, which gives a certain level of water resistance. Plus, they are lightweight and durable.
We add technologies such as membranes or Durable Water Repellent( DWR) treatments to these fabrics, to transform them from water-resistant to fully waterproof. These DWR coatings make water bead-up and roll off the surface of the fabric rather than soaking in.
Traditional DWR finishes contain environmentally harmful perfluorinated chemicals( PFCs). Many manufacturers are switching to less harmful treatments, but these require more frequent reapplication. This is because the waterproofing chemicals gradually wash away with the rain.
A fabric is considered waterproof if it can withstand a certain amount of water pressure without letting moisture through. This is measured using the hydrostatic head test. The industry standard for waterproofing is a hydrostatic head rating of at least 1,500mm, meaning the fabric can hold a column of water 1,500mm tall without leaking.
A hard rain might generate around 2 psi( equivalent to about 1,400mm hydrostatic head pressure). Sitting can generate about 7 psi, and kneeling about 18 psi. Thus, waterproof fabrics need to withstand much higher pressures than just rain to ensure they keep us dry in real-world conditions.
Breathability in a waterproof fabric substantially adds to our warmth and comfort. Microporous membranes have tiny pores that are small enough to block liquid water from entering, but large enough to allow water vapour out. By contrast, hydrophilic coatings work by absorbing moisture vapour and then moving it through the fabric to the outside by diffusion.
Nature, of course, is way ahead of us. The humble pond skater has a special waxy coating on the tiny hairs on its legs. Another example is lotus leaves, which
The waxy coating of a pond-skater could be the key to next gen waterproofing tech
“ Nature, of course, is way ahead of us”
have nanotexture and hydrophobic wax crystals. These waxy substances and nano-textures are coveted by human designers and materials scientists because they could help us create lightweight, permanently water-repelling fabrics.
Researchers at the forefront of innovation are experimenting with nano-textures and nanoparticle coatings that could redefine waterproof materials. These nanoparticles could create an ultra-thin layer impenetrable to water at the molecular level, potentially resulting in fabrics that are lighter, thinner, and more breathable than ever before.
Imagine a sustainable nano-drysuit! An innovative suit that uses nano-textured fabric to be fully waterproof, lets sweat out, is lightweight, durable, and quickdrying. Or … perhaps this nanotechnology will be too good at repelling water. Meaning that rather than having an amazingly dry dive, we’ d be stuck on the water’ s surface flailing around like the most inelegant pond skaters ever.
Either way, I’ m sure these amazing new waterproof technologies will be a reality within my lifetime. The big question, however, is can we make them sustainably? �
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