Fluorocarbons – PFOS, PFOA and things that keep you dry.
Water repellent treatments work by lowering the surface energy of a fabric so water beads off instead of wetting out.
Waxes, Oils and Silicones all are used to achieve this – but also are all affected by oils – such as those coming off our skin during use.
Fluorocarbons, particularly PFOS (perfluorooctane sulfonate) and PFOA (perfluorooctanoic acid) are effective at effective at repelling both water and oil – so for a long time were used by outdoor equipment manufacturers to create waterproof systems.
However, a couple of years ago, data related to the potential health and safety concerns emerged in regards to both PFOS and PFOA. They are both now considered a ‘likely carcinogen’ ((A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes.)).
Greenpeace called for their ban ((http://blog.stepchange-innovations.com/2013/07/greenpeace-puts-pressure-on-outdoor-brands-to-phase-out-fluorocarbon-chemistry/)), and NikWax campaigned to get rid of them ((http://www.grough.co.uk/magazine/2013/12/17/outdoor-boss-warns-uk-industry-of-gathering-storm-over-waterproofing-chemicals)).
Newer, safer, but better?
So, manufacturers have been moving away from the PFOS and their ilk. Generally this has meant shorter chain chemicals – they break down faster in the environment and cause less (reported) health effects. The downside? They don’t work as well. They are getting better, but they don’t work as well.
But wait – aren’t there new, better materials coming out all the time?
Gore Tex, Event, there is a newer material coming out every couple of months at the moment – all promising faster, better more breathable and more waterproof.
Remember though – there is two parts to a waterproofing system – the fabric (Gore Tex, Event and all) which is what effects breathability and the DWR coating, which is what keeps the water out of the fabric in the first place. Yes, the materials are getting better.
There is plenty of ongoing experiment and testing – but fundamentally, we had to take a step backwards and are still catching back up.