Roll-to roll Initiated Chemical Vapor Deposition of Super Hydrophobic Thin Films on Large-Scale Flexible Substrates

Abstract In this study, a large-scale roll-to-roll initiated chemical vapor deposition (iCVD) system was developed to allow for coating superhydrophobic thin films on flexible substrates. Poly(hexafluorobutyl acrylate), which possesses a short fluorinated side-chain, was chosen as the hydrophobic finish material, while a commercial porous bamboo fabric was used as the flexible substrate. After iCVD coating, bamboo surface, which is superhydrophilic by its nature, transformed into a superhydrophobic with a water contact angle of 156° without changing its porous and flexible structure. Similar hydrophobic properties were observed against various daily liquids. Complete coverage of as-deposited films on both sides of bamboo surfaces was observed at very high roll speeds up to 225 mm/min, which allow coatings on 20 m2 flexible substrates in a single run. Large scale contact angle and chemical uniformity of coatings on fabric surfaces were evaluated using contact angle and XPS analyses.