A polymeric coating can de-ice large surfaces

Materials World magazine
,
29 May 2019

A new coating that can be made from any polymeric material allows for instant de-icing of large surfaces. Idha Valeur reports.

Removing ice from large surfaces is possible by using low interfacial toughness (LIT) materials.

The process creates a domino-like motion. LIT materials allow cracks to form between ice and the surface it sits on, ‘to easily propagate along the interface, effectively de-iceing the entire surface at once,’ University of British Columbia, Canada, Assistant Professor and lead author of the study, Kevin Golovin, told Materials World.

When designed correctly, any polymeric material could be used to make a coating that has the desired de-icing effect, dislodging adhered ice no matter how large the area.

‘What we’ve discovered is a method of imbuing low ice-adhesion properties into any material system by lowering the interfacial toughness with ice. Because of this, we’ve demonstrated remarkably low ice-adhesion with a range of different starting materials. They can be bio-based, food-grade, transparent, recycled and so on,’ Golovin said.

According to Golovin, LIT materials are changing how scientists understand ice-adhesion. ‘For example, ice-phobic materials, the ones that lower the ice-adhesion strength but not toughness, are improved by increasing the thickness of the coating. In contrast, LIT materials are more effective for very thin coatings,’ he said.

‘Further, LIT materials can exhibit high ice-adhesion strengths, but this does not impact their superior de-icing properties for large surfaces. So not only are LIT materials optimised differently from ice-phobic materials, but there’s also little overlap between the two technologies.

‘This means materials that were previously ruled out for their high ice-adhesion strengths might perform well as LIT materials, which opens the door in terms of possible material composition candidates.’

Benefits and applications

Another benefit of this new coating is the force required is much smaller. ‘[Normally] de-icing an ice cube tray utilising ice-phobic coatings is easy, but removing ice from a windshield is more difficult, and an airplane wing more difficult still. In contrast, LIT materials require the same low force in all three of these applications,’ Golovin said. Icy surfaces present problems – trying to scrape the windshield of a car is a nuisance but when preparing an aeroplane for departure, it can be high risk. ‘Icing is dangerous, and mitigation measures are costly, time-consuming, and hazardous to the environment,’ Golovin said.

‘If planes did not require de-icing, airports and airplanes would become more efficient. If wind turbine blades didn’t get locked by ice in the winter time, they could run all year round. If powerlines and bridge cables didn’t accrete ice, they would be safer for all that live in ice-prone regions of the world. Ice accumulation is a huge problem in cold regions and reducing or even eliminating the problem would be incredibly beneficial.’

Another plus is the easy manufacture process of the coating. Golovin explained that because toughness is a generic material property, the base materials required to fabricate LIT coatings can be selected from a wide range of options. ‘Some of the materials we demonstrate in our work are fabricated from common plastics and natural oils like coconut or safflower oil,’ he said. ‘LIT properties can be engineered into common paints and coatings so the commercialisation barriers are quite low.’

Funding and future

According to Golovin, anything large, cold and iced could benefit from LIT materials including aeroplane wings, helicopter blades, hydroelectric dams, powerlines, wind turbine blades, boat hulls, HVAC systems and roads. He added that different application areas will have different durability requirements – an aerospace coating will need to be much more robust than one for powerlines. ‘As such, the first application areas of LIT materials will most likely be inside automatic ice makers and on heat exchangers. We’re actively seeking commercial partners and investors in order to bring all variants of LIT materials to market,’ he said.

Some of the coating systems, their specific material compositions, are currently at technology readiness level (TRL) 5-6. Prototypes are actively being tested on real structures in Canada, Golovin explained.

Golovin’s team received partial funding from The US Department of Defense for ocean-faring vessels in the far North. ‘Sea water that splashes onto boat hulls in sub-zero conditions has a tendency to freeze, and frozen walkways are extremely hazardous for Navy personnel,’ Golovin explained. ‘I believe the Office of Naval Research also saw the potential in developing new methods for de-icing from a broader perspective, such as for some of the various applications mentioned.’