Development of superhydrophobic coating on paperboard surface using the Liquid Flame Spray

This paper introduces a new method for generating nanoscale coatings in a continuous roll-to-roll process at normal pressure. Nanostructured and transparent coating, based on titanium dioxide nanoparticles, was successfully deposited on-line at atmospheric conditions on pigment coated paperboard using a thermal spray method called the Liquid Flame Spray (LFS). The LFS coating process is described and the influences of process parameters on coating quality are discussed. Nanocoating was investigated by a field emission gun scanning electron microscope (FEG-SEM), an atomic force microscope (AM), an X-ray photoelectron spectroscopy (XPS) and a water contact angle measurement The highest measured water contact angles on the nanocoated paperboard surface were over 160 degrees. Falling water droplets were able to bounce off the surface, which is illustrated by high speed video system images Regardless of the high hydrophobicity, the coating showed sticky nature, creating a high adhesion to water droplets immediately as the motion of the droplets stopped Nanocoating with full coverage of the substrate was produced at line speeds up to 150 m/min. Therefore, the LFS coating has scale up potential to industrial level as an affordable and efficient method for coating large volumes at high line speeds. (C) 2010 Elsevier B.V. All rights reserved.