On Fundamentals and Applications of Superhydrophobicity in Papermaking and Packaging

Abstract

Fundamental material science investigations of superhydrophobicity in recent years has evolved toward industrial applications and recently to papermaking and packaging. The present study concerns both fundamental and applied aspects of superhydrophobicity. An industrially viable process for a one-step waterborne superhydrophobic coating was developed. It is shown that different measures of the degree of superhydrophobicity are needed depending on the final application whether this may be self-cleaning or stain repellent action. Fundamental aspects of superhydrophobicity were investigated using silica wafers roughened by a particulate formulation containing nanosize silica particles, which were fixed to the substrate by calcination. After hydrophobization by silylation, the forces between a colloidal superhydrophobized silica probe, made according to a similar procedure, and these surfaces were measured by Atomic Force Colloidal Probe Microscopy. The results show an extremely long range interaction force and a large influence of surfactant and surfactant concentration. The results would prove useful in designing robust superhydrophobic application in the papermaking and packaging industry and also imply that coating and printing technique could be used for controlled deposition of superhydrophobized layers or areas.