This interdiscipilinary team investigated alternatives to perfluorinated compounds for DWR (durable water repellency) in outdoor clothing. The Gore team was challenged to create a high-performance fabric treatment that could resist both water and oils. They recommended silica nanosols and blow spinning as the two most promising solutions; these reported the best hydrophobicity, potential for oleophobicity, and application to textiles.
A silica nanosol coating provides hierarchical structuring through silica nanoparticles that bond with the surface of a synthetic fabric (e.g. polyester). Silica nanosols are highly hydrophobic but not as oleophobic as desired. The team suggested adding a liquid-like coating such as dimethyldimethoxysilane to the silica solution to improve oleophobicity.
Blow spinning is a process to create textured, microfiber mats which are hydro- and oleophobic, similar to the Silver Ragwort leaf. Blow spinning seemed less hazardous than other processes (such as electrospinning) since the process uses a non-toxic compressed gas (i.e. air or argon) and can use ethanol or propanol as a solvent for a variety of synthetic polymers that then form the fibers. The team recommended that Gore use blow spinning to create microfiber mats to coat their clothing textiles.