Nanostructured article

A nanostructured article comprising:

• a substrate;
• and
• a plurality of first nanostructures disposed on the substrate, the plurality of first nanostructures comprising covalently crosslinked polyurethane having a crosslink concentration in a range from 0.3 to 1.05 mol/kg, the plurality of first nanostructures extending away from the substrate along a length of the first nanostructures, the plurality of first nanostructures having an average length L1 and an average width W1, W1 being in a range of 5 nm to 500 nm, L1/W1 being at least 1;
• and
• a covalently crosslinked fluorinated polymeric layer disposed on the plurality of first nanostructures and at least partially filling spaces between the first nanostructures to an average minimum height above the substrate of at least 30 nm such that the polymeric layer comprises a nanostructured surface defined by, and facing away from, the plurality of first nanostructures,
• wherein the nanostructured surface of the polymeric layer comprises a plurality of second nanostructures, each second nanostructure in at least a majority of the second nanostructures at least partially surrounding a plurality of the first nanostructures,
• wherein the first nanostructures extend to an average height H1 from the substrate and the plurality of second nanostructures have an average peak-to-valley height H2, H2 being less than 0.7 H1.

A nanostructured article comprising a polyurethane layer and a plurality of first nanostructures integrally formed on the polyurethane layer, the polyurethane layer comprising covalently crosslinked polyurethane having a crosslink concentration in a range from 0.3 to 1.05 mol/kg, the plurality of first nanostructures extending away from the polyurethane layer along a length of the first nanostructures, the plurality of first nanostructures having an average length L1 and an average width W1, W1 being in a range of 5 nm to 500 nm, L1/W1 being at least 1;

• and
• a covalently crosslinked fluorinated polymeric layer disposed on the plurality of first nanostructures and at least partially filling spaces between the first nanostructures to an average minimum height above the substrate of at least 30 nm such that the polymeric layer comprises a nanostructured surface defined by, and facing away from, the plurality of first nanostructures,
• wherein the nanostructured surface of the polymeric layer comprises a plurality of second nanostructures, each second nanostructure in at least a majority of the second nanostructures at least partially surrounding a plurality of the first nanostructures,
• wherein the first nanostructures extend to an average height H1 from the substrate and the plurality of second nanostructures have an average peak-to-valley height H2, H2 being less than 0.7 H1.