Surface modification of cotton fabrics by gas plasmas for color strength and adhesion by inkjet ink printing

Surface properties of cotton fabric were modified by three types of gas plasma pretreatment, namely, oxygen (O-2), nitrogen (N-2) and sulfur hexafluoride (SF6), to improve ink absorption of water-based pigmented inkjet inks and color reproduction of the treated surfaces. Effects of gas plasma exposure parameters of power, exposure time and gas pressure on surface physical and chemical properties of the treated fabrics were investigated. XPS (X-ray photoelectron spectroscopy) was used to identify changes in functional groups on the fabric surface while AFM (atomic force microscopy) and SEM (scanning electron microscopy) were used to reveal surface topography of the fabric. Color spectroscopic technique was used to investigate changes in color strength caused by different absorptions of the printed fabrics. The O-2 plasma treatments produced new functional groups, -O-C-O/C=O and O-C=O while N-2 plasma treatments produced additionally new functional groups, C-N and O=C-NH, onto the fabric surface which increased hydrophilic properties and surface energy of the fabric. For cotton fabric treated with SF6 plasma, the fluorine functionalization was additionally found on the surface. Color strength values (K/S) increased when compared with those of the untreated fabrics. SF6 plasma-treated fabrics were hydrophobic and caused less ink absorption. Fabric surface roughness caused by plasma etching increased fabric surface areas, captured more ink, and enhanced a larger ink color gamut and ink adhesion. Cotton fabrics exhibited higher ink adhesion and wider color gamut after the O-2 plasma treatment comparing with those after N-2 plasma treatment. (C) 2015 Elsevier B.V. All rights reserved.