Initiated chemical vapor deposition of poly(hexafluorobutyl acrylate) thin films for superhydrophobic surface modification of nanostructured textile surfaces

This study demonstrates the synthesis of poly(hexafluorobutyl acrylate) (PHFBA) thin films on textile substrates using initiated chemical vapor deposition (iCVD) method. Owing to its short perfluoroalkyl functional group, PHFBA is a suitable low-surface-energy finish that can be used for hydrophobic functionalization of textile surfaces. During iCVD of PHFBA, the use of initiator helped to achieve deposition rates up to 83 nm/min, which is nearly twice that achieved by PECVD. FTIR and XPS analyses of as-deposited films showed very high retention of carbonyl and perfluoroalkyl functionalities. Polyester and cotton fabrics were made superhydrophobic after conformal coating of PHFBA by iCVD. The decoration of fabric surfaces by SiO₂ nanoparticles prior to the iCVD coating helped to create composite structures having dual-scale roughness. The final SiO₂-treated and iCVD-PHFBA-coated textile fabrics showed very high water contact angles (> 165°).