TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The microstructures are prisms. The prisms have a peak angle of 90 degrees . The prisms have a peak angle of 74-76 degrees . The metal oxide is indium tin oxide. The indium tin oxide nanoparticles have an average diameter of 70-100 nm.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The microstructures are microlenses. The silicone polymer is polydimethylsiloxane. The microstructures and nanofeatures comprise polydimethylsiloxane (at least 95 wt.%). The nanofeatures are formed into the microstructures by reactive ion etching. The microstructures are reactive ion etched using an etch mask of nanoparticles. The nanoparticles are composed of a metal oxide. The microstructures and nanofeatures are formed by a replication process. The microstructures have an average height of 0.15-1000 microns. The nanofeatures have an average height of 10-1000 nm, an average width of 5-250 nm, and an average aspect ratio of at least 4-1 (preferably at least 6-1). The microstructures are shaped and arranged in a pattern that mimics sharkskin. The microstructures are varied in at least one of three dimensions. The microstructures and nanofeatures do not have any low surface energy coating applied to them. The film maintains a water contact angle of greater than 145 (preferably greater than 160) degrees and a sliding angle of less than 10 (preferably less than 5) degrees after a falling sand exposure test. The adjacent microstructures have an average peak-to-peak distance of 0-5 times an average height of the microstructures. The etching the film comprises reactive ion etching the film. The microstructures and nanofeatures comprise a material that is an elastomer. Preferred Method: In the method, the layer of metal oxide nanoparticles is applied uniformly; the layer of metal oxide nanoparticles is applied as part of a coating suspension mixed with isopropanol; the metal oxide is 0.1-2 wt.% of the coating suspension; the etching by reactive-ion etching; the metal oxide nanoparticles etch at slower rate than the film; silicon dioxide is not used in the etching step; the nanofeatures are etched to have an average height of 10-1000 nm; and the etched film has a water contact angle of at least 170 degrees and a sliding angle of less than 2 degrees . The method does not include a step of applying a hydrophobic coating onto the microstructures and nanofeatures. The producing a superhydrophobic film involves providing a first film comprising microstructures on a first surface of the film; applying a uniform layer of metal oxide nanoparticles directly onto the microstructures; etching the film, using the metal oxide nanoparticles as an etch mask, where the etching results in nanofeatures formed into the microstructures of the first film; depositing a casting material onto the first film; forming a mold with the casting material, where the mold comprises a negative of the microstructures and nanostructures of the first film; applying a silicone polymer to the mold; curing the silicone polymer into a second film; and removing the second film from the mold, where the second film having a water contact angle of at least 150 degrees and a sliding angle of less than 10 degrees . EXAMPLE - No suitable example given.