A SUSTAINABLE APPROACH TO WATERPROOFING: C0 DWR and the Shift Away from Forever Chemicals

Durable Water Repellent (DWR) is a critical component in outdoor apparel, ensuring that rain jackets, trousers, tents, and other technical gear remains water-resistant. However, the environmental impact of traditional DWR formulations has raised concerns. DWR is an ultrathin polymer-based coating applied to fabric exteriors. It prevents water absorption by increasing the contact angle between the fabric surface and moisture particles. As a result, water beads up and rolls off, rather than saturating the fabric. However, DWR’s water-resistance is temporary, wearing away over time due to normal use and contact with other materials. .

PFAS, often called “forever chemicals,” pose a global challenge. These per- and polyfluoroalkyl substances are prized for their indestructible and non-stick properties. They exist in saucepans, clothing, and cosmetics, more recently though they have started to appear in rainwater and even our blood. PFAS persist for tens of thousands of years, accumulating in the environment. Their mobility allows them to escape landfills and bioaccumulate in organisms, affecting humans and wildlife alike.

The concept of enhancing fabric water-resistance dates back centuries. Early explorers discovered that treating ship sails with linseed oil improved their ability to shed water, while Sir Ernest Shackleton’s ’s own men used a twill gabardine fabric that was made from Egyptian cotton yarns that were waterproofed using lanolin before and after weaving. However, it was the advent of GORE-TEX® multilayer fabrics in the late 20th century that brought waterproofing technology into the mainstream. The first chemical-based Durable Water Repellent, known as C8 (long-chain fluorocarbon-based treatment), emerged in 1969.

While C8 DWR effectively repelled water, it came with significant drawbacks. By-products of C8 chemistry are toxic and persist in the environment. Governments worldwide have mandated the discontinuation of C8 DWR production. As a result, outdoor gear manufacturers sought alternatives that balance performance with environmental safety.

C6 DWR, a shorter-chain fluorocarbon-based treatment, emerged as a more responsible option. It still contains perfluorooctane sulfonate (PFOS), but its environmental impact is lower than C8. However, C6 DWR remains a temporary solution, as it is not entirely free from environmental concerns.

C0 DWR represents a cleaner, safer choice. Unlike C6 and C8, it is entirely free from perfluorinated chemicals (PFCs). C0 DWR maintains exceptional water-repellency, matching C6’s performance without the environmental drawbacks. However, C0 DWR doesn’t exhibit the same water beading properties as C6 or C8. This may lead to treated materials appearing to “wet out”, although visually not as satisfying, as long as underlying materials are made from water resistant membranes you can be assured to remain as dry as any product treated with harmful forever chemicals. 

As the outdoor and wider industries evolve, responsible fabric treatments become paramount. C0 DWR offers a promising path forward, balancing performance, human health, and environmental impact. Although we must continue researching and developing safer alternatives, ensuring that waterproof gear remains effective without compromising our planet’s well-being, for the time being there really is no excuse not to choose the most responsible option.