The present disclosure provides advantageous composite films/coatings, and improved methods for fabricating such composite films/coatings. More particularly, the present disclosure provides improved methods for fabricating composite films by trapping at least a portion of a layered material (e.g., hexagonal boron nitride sheets/layers) at an interface of a phase separated system and then introducing the layered material to a polymer film. The present disclosure provides for the use of boron nitride layers to increase the properties (e.g., dielectric constant and breakdown voltage) of polymer films. The exemplary films can be produced by an advantageous climbing technique. Exemplary boron nitride films are composed of overlapping boron nitride sheets with a total thickness of about one nanometer, with the film then transferred onto a polymer film, thereby resulting in significant increases in both dielectric and breakdown properties of the polymer film.