Article (9,19) comprising a substrate (10, 20) comprising a polymer and having first (11,21) and second (12, 22) opposed major surfaces. The first major surface (11, 21) has first surface regions (13, 23) with first nanoparticles (14a, 14b, 14c, 14d, 24a, 24b, 24c, 24d) partially embedded into the first major surface (11, 21), and one of •(a) second surface regions (15) free of nanoparticles; or •(b) second surface regions (25) with at least second nanoparticles (28) on the first major surface (11, 21) or partially embedded into the first major surface (11, 21). The first surface regions (13, 23) have a first average surface roughness, Ra1, of at least 20 nm, wherein the second surface regions (15, 25) have a second average surface roughness, Ra2, of less than 100 nm, wherein the first average surface roughness, Ra1, is greater than the second average surface roughness, Ra2, and wherein there is an absolute difference between the first and second average surface roughness of at least 10 nm.