Morphology and Discharge Parameter Dependence of Property and Structure of RF Sputter-Deposited Fluorocarbon Coatings on PET Fibers

Radio frequency (RF) sputtering has been employed to fabricate a series of polymeric fluorocarbon coatings on PET fibers for a novel waterproof breathable fabric(WBF). SEM images reveal that the coating morphology on PET fibers is different form that on PET film under same discharge parameters. Numerous wire-like micro⁄nano-sized particles have formed on the PET fiber surface, whereas 3-dimensional network consisting of numerous lying silkworm-like micro⁄nano-sized particles has been created on the PET film substrate. The water contact angle of the WBFs was found to decrease remarkably with power but to rise with pressure due to the changes in the coating composition. The deposition time mainly affects coating thickness other than composition. The moisture permeability of these coated fabrics is near that of the uncoated fabrics since only the fiber surface has been individually covered with the coated grains while the fabric still remain original numerous pores. It was found that an increased target-substrate distance (TSD) leads to a decrease in deposition rate, while decreased TSD can make the coating more uneven. The contact angle of the coated specimens obtained at higher energy is always smaller than that obtained at lower energy for a given washing time, attributed to formation of more fluorine-lack groups in the former.