David Gygi

Coating solid surfaces with cellulose nanofibril (CNF) monolayers via physical deposition was found to keep the surfaces free of a variety of oils, ranging from viscous engine oil to polar n-butanol, upon water action. The self-cleaning function was well correlated with the unique molecular structure of the CNF, in which abundant surface carboxyl and hydroxy groups are uniformly, densely, and symmetrically arranged to form a polar corona on a crystalline nanocellulose strand. This isotropic core–corona configuration offers new and easily adoptable guidance to design self-cleaning surfaces at the molecular level. Thanks to its excellent self-cleaning behavior, the CNF coating converted conventional meshes into highly effective membranes for oil–water separation with no prior surface treatment required.

Simple coating of cellulose nanofibril (CNF) monolayers brings about excellent self-cleaning surface behavior. Thanks to its isotropic molecular configuration, the orientation of each CNF with respect to the surface plane hardly affects water wetting on the CNF coating, thus making the coating surfaces clean of a variety of oils upon simple water action.