ABSTRACT:The fundamental mechanism of wetstrength development for dielectric-barrier discharge treated thermomechanical pulp fibers was explored. Electron spectroscopy for chemical analysis (ESCA), vapor phase fluorine surface derivatization followed by ESCA, and dynamic contact angle analysis were performed to assess the surface chemistry in terms of both chemical functionality and wettability. Effects of the intensity of dielectric-barrier discharge treatment on the surface chemistry of lignocellulosic fibers and the corresponding impacts to fiber wet-tensile properties are described. This study indicates that low treatment intensities result in increased wettability due to surface oxidation, which leads to a small reduction in wet-tensile index. However, increased treatment intensity brings about diminished wettability due to covalent crosslinking, which leads to increases in wet-tensile index.