“We need to energise a consortium to use coatings to reduce atmospheric carbon”

The US company Reactive Surfaces has developed a carbon capture coating technology. We spoke with Dr Steve McDaniel about his his company’s plan to find partners for a joint effort to fight against global warming. 

"The timelines to achieve a large drawdown of the carbon dioxide in the atmoshpere are frighteningly short" -

What are carbon capture coatings?

Dr Steve McDaniel: First and foremost they are real coatings, polymeric materials that can be thinly spread on a surface. They will tightly adhere to the surface and cure. What’s cool about them: when you cure them on a surface and you expose them to sunlight, they will photosynthesise and capture the carbon, fix that carbon, and using the photosynthetic process turn it into carbohydrates. And in this particular case, because of the modified algae we’re using, they sequester the glucose into a polysaccharide, like cellulose.This photosynthesis requires carbon dioxide and water.

Because the algae require water we have to make sure these coatings can be hydrated and rehydrated easily, and that they can remain hydrated. Because they are hydrated, you want to make sure that they don’t develop mould and mildew and that they have free exchange of atmospheric gases. They need to sequester carbon dioxide and then at least to release oxygen.Also, they have to be translucent to sunlight.


How can these coatings help to balance the output of carbon dioxide?

McDaniel: It’s a gargantuan problem. In 2018 we as a species emitted 31.7 billion tons of carbon dioxide into the atmosphere, primarily from the combustion of fossil fuels.

The response, the way we’re going to fight this, has to be equally large. I think that the coating industry is uniquely situated to do that because one of the things we do in this business is coat very large amounts of surface area. And this surface area will act as a giant filter to the atmosphere. I can’t think of any other industry that can do this kind of thing.

How did you come up with this approach?

McDaniel: We’re an innovation company, we are located near the University of Southern Mississippi, so we have a ready access to a lot of scientists – it’s a team effort. At Reactive Surfaces we go into nature and take out functionality, e.g. an enzyme or a peptide, then we entrain it into a coating and ask it to do what it did in nature in the fixed coating. I have always toyed with the possibility that it might be possible to actually entrain living cells.

The idea was: is it possible to basically replicate the ability of algae in lichen, because they almost look and act like a coating, if you have ever seen them on a rock? We didn’t know for sure if we could, but we have done it.

How far have you come so far with this technology?

McDaniel: We have several generations of coatings so far. We have’t met a polymer system yet that we don’t like. We  entrain algae in this, and the algae not only survive but thrive. The surfaces get quite green. They are actually very pretty.

Please briefly explain the mechanism of your technology.

McDaniel: The reason that we’re using plastic bottles for this is because they are readily available, they are translucent and they block a little bit of UV, as the organisms can’t take too much UV. They allow us to keep the hydration level quite high.

The technology is basically this: we take genetically modified organisms and we make these algae overproduce cellulose. When we entrain them in a coating, and they receive sunlight, they will combine carbon dioxide with the capture, and they will then convert that carbon dioxide with molecular water and the photon of sunlight to produce a polysaccharide. These particular algae are good at taking that polysaccharide – glucose in this case – and combining it up into a polysaccharide cellulose, and that polysaccharide just gathers in the coating. These coatings are rather elastic and expand, and so you gather a lot – maybe as much as four to five times the weight of a coating in cellulose. Cellulose of course is a commodity. That’s how it works.

Why are you using plastic bottles, while everyone is talking about the problem of plastic waste, microplastics etc.?

Reactive Surfaces Carbon Capture bottles

Plastic bottles provide a lot of translucent surface to test the new coating.

McDaniel: I actually don’t like to focus on plastic bottles. In the lab you’re trying to do things the cheapest way you can. So when we knew we had the coatings, we needed a whole lot of translucent surface area upon which to test them, ergo the bottles in sleeves. If these coatings are going to pull down the amount of carbon that’s in the air, they have to be painted on massive amounts of surface area. You can make your own surface area if you use for instance bottles or plastic sleeves, and that’s what we were looking for.

Obviously, the bright folks in the industry will come up with all sorts of different surfaces, if we can pull together a consortium, like I hope we can.

Talking about a possible consortium: how could this come about?

McDaniel: The timelines to achieve a large drawdown of the carbon dioxide in the atmoshpere are frighteningly short. No one company can do it that quickly. We need to energise a consortium within the industry that already has distribution networks, knows how to build coatings, has the polymer and additive chemists, the supply chains, all of that ready to go. If we could do that, there would be a pretty good chance that we as an industry could take a big bite out of the anthropogenic (human-caused) atmospheric carbon dioxide.

How can companies become involved?

McDaniel: We’re beginning to challenge the technology. We will give it a good scientific analysis. Then we hope that people will take the technology in-house and we’re going to make it very simple for them to do so. They can reach us on our website, by phone and e-mail. I hope that by the end of the year we’ll have a consortium of different companies that have these coatings in their own polymer laboratories actually working.

I’m not only talking about coatings manufacturers, but the distribution side of it as well as the supply side. It will be important to use all of the technical and intellectual assets that we have as an industry, and then realise where we don’t have a necessary expertise, say in algae production, rapidly work with someone who can contribute that expertise.

Are there still obstacles to be overcome in terms of regulations, raw material supply etc.?

McDaniel: The good news on the raw material side is at least the coatings we have right now are based on renewable resources. They are polymers that are made from algae themselves or by bacterial fermentation. These resources are sort of endless. As far as regulatory road blocks are concerned, we were very cognisant of this from the very beginning because, again, speed is very important, we don’t have time to slow down. And by the way, we should all be very thankful that the regulatory people around the world are protecting the environment and human health. Let us hope that they are going to do a very good job, but let’s also give them an easy job. Let us use renewable resources. What we’re hoping is that the coatings industry starts working with the regulatory people from the very beginning, so that there won’t be any road blocks.

The interview was conducted by Kirsten Wrede.

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