Breathable polyurethane membranes for textile and related industries

This Application article briefly reviews the science behind so-called “breathable” coatings and films, designed originally for foul-weather garments. These materials form continuous polymer layers over a textile substrate, which are impermeable to liquids such as rainfall and yet transmit water vapour emitted from the body. Some bear many similarities to dense membranes used for ultra-filtration and reverse osmosis. Hydrophilic polyurethanes containing poly(ethylene oxide), PEO-PUs, form a distinct class that straddle the ill-defined boundaries between conventional macromolecular chemistry, nanotechnology, biomimetics and smart materials. The unique properties and bio-compatibility of PEO provide further opportunities for these polymers in diverse areas such as packaging, medical devices, controlled-release systems, hydrogels, electronics, and biosensors.