Material for winding high voltage capacitors is prepared by evaporating polyfunctional acrylate monomer having a molecular rate in the range of from 150 to 600 and condensing the acrylate as a monomer film on a dielectric substrate. The acrylate is polymerized by irradiation by ultraviolet or electrons. Sometimes both faces of the dielectric are coated to protect the thermoplastic dielectric from swelling when exposed to dielectric liquid. The metallized layer provides an electrode of the capacitor. A polymerized acrylate layer may be applied over the metal layer. Electrical contact can be made to the metal layer by Schooping even though the metallized layer is covered by a layer of acrylate. Low oxygen permeability polypropylene, polyester or nylon sheet has a layer of crosslinked acrylate and an oxygen barrier layer formed of silicon oxide, aluminum oxide or metal. Adhesion is enhanced by plasma or corona treatment of a surface immediately before deposition. Condensation efficiency is also enhanced by chilling the substrate on which the acrylate is condensed.