Fundamental studies of superhydrophobicity have evolved toward several industrial applications. The present study concerns the formulation of pigmented foam aimed for water-borne superhydrophobic surface layers. An industrially viable process for a one-step water-borne superhydrophobic coating was developed in collaboration with industrial partners. A typical formulation contained calcium carbonate (preferably aragonite type), sodium oleate and carboxylic latex binder. The pigmented foam was laboratory rod coated onto paperboard substrates. During the drying the foamed structure collapses into a pigmented coating. The contact and rolling-off angles, droplet stain size and Cobb value were evaluated for different amounts of the added ingredients. The frictional resistance and water vapour permeability was measured for some of the samples.
More recent results show that through careful reformulation of the coating dispersions these pigmented foams can be prepared at considerably higher solids content, which is of utmost relevance to decrease drying time if implemented in an industrial process. It was also shown that the hydrostatic water resistance (Cobb value) and the mechanical robustness could be substantially improved compared to previous results. Surface spectroscopy data provided an explanation for the increased water resistance.
SP Chemistry, Materials and Surfaces publication nr: B1618