Functional surfaces produced by foam coating

This paper reports experiments on silica coating formulations that are suitable for applying a thin pigment layer with foam coating technique on a paper web. To understand the foaming properties of nano-silica dispersions, the critical micelle concentration (CMC), foam half-life time and foam bubble size stability were determined with three different foaming agents. The results indicate that the bubble stability measurement is a useful characterization method for foam coating purposes. Pilot foam coating trials were done and the effects of the chosen foaming agents were studied on the properties of the nano-silica coated paper. The results show that the surface hydrophilicity of silica coated paper was related not only to silica pigment, but also to the chemical nature of the foaming agent. Standard paper properties were not affected by the thin silica coating.