Cellulose nanofibers as binder for fabrication of superhydrophobic paper

This study reports the preparation of superhydrophobic paper via a facile two step dip coating method. In the first step, filter paper samples were dip coated using an aqueous suspension containing Precipitated Calcium Carbonate (PCC) pigments and cellulose nanofibers, to form a highly rough layer on the surface of the filter paper. Subsequently, the coated papers were treated with a solution of alkyl ketene dimer (AKD) in n-heptane, which led to the formation of superhydrophobic paper. Contact angle measurements confirmed the superhydrophobic nature of the paper prepared. SEM analysis was also carried out to characterize the surface differences of the coated paper samples with and without the added cellulose nanofibers and to clarify the binding role of cellulose nanofibers. It was observed that cellulose nanofiber is a critical component to the formation of the rough PPC coating layer required for giving superhydrophobicity; it significantly improves the retention of PCC clusters on the surface of the paper and the retained PCC clusters offer the structure of dual scale roughness.