A method of making nanostructured polymeric film includes: providing a tool having a porous anodized aluminum surface or a metallic replica thereof, wherein the average depth of the pores and the average pore width fall with specified ranges; forming a continuous layer of thermoplastic polymer selected from cellulose esters, poly alpha-olefins, and combinations thereof on at least a portion of the surface of the tool such that the continuous layer extends into the pores of the surface; separating the continuous layer from the tool as a film having nanofibrils formed on a major surface of the tool, the surface of the tool having a fluorocarbon release agent thereon, or the continuous layer comprising a fluorocarbon melt additive, or both. Nanostructured films are also disclosed.