Water-repellent coating

MIT researchers have demonstrated a technique for depositing a very thin layer of a water-repellent coating that will make it possible to waterproof new kinds of materials.

MIT researchers have demonstrated a technique for depositing a very thin layer of a water-repellent coating that will make it possible to waterproof new kinds of materials and may offer ways to combine waterproofing with antibacterial and other active coatings.

The technique has many potential applications, including fabric coatings for soldier’s uniforms, coatings for fine wire neural probes and insulation for integrated circuits.

Researchers working with Professor Karen Gleason of the Department of Chemical Engineering have used a process called hot filament chemical vapour deposition (HFCVD) to deposit nanolayers of polytetrafluoroethylene (PTFE, also known as Teflon). They have used the process to waterproof ordinary cotton T-shirt fabric, which retains its breathability and is indistinguishable in look and feel from untreated fabric.

Unlike many commercially available waterproofing processes, the HFCVD process deposits the coating from the vapour phase, offering the potential to coat materials that cannot be immersed in a solution or that have unusual geometries.

‘For example, the US Army is interested in waterproofing bullet-proof panels made of Kevlar,’ Gleason said. ‘Because of Kevlar’s chemical characteristics, some of these other solution-based techniques wouldn’t necessarily even wet it.’

The work was sponsored by the NIH and the US Army (through MIT’s Institute for Soldier Nanotechnologies).