We have recently shown that the capillarity-based process for self-assembling particle monolayers on fluid-liquid interfaces can be improved by applying an electric field in the direction normal to the interface. In this paper, we present a technique for freezing monolayers of micron-sized particles onto the surface of a flexible thin film. Micron sized particles do not self-assemble under the action of lateral capillary forces alone since capillary forces among them are small compared to Brownian forces. The technique involves assembling the monolayer on the interface between a UV-curable resin and a fluid which can be air or another fluid by applying an electric field, and then curing the resin by applying UV light. The monolayer becomes embedded on the surface of the solidified resin film.