The present invention provides a polymer coating method. In the method, in a vacuum chamber, a low temperature monomer evaporation chamber is used to heat a liquid monomer and a cooled substrate at a temperature lower than the liquid monomer reservoir or vapor. The liquid monomer is allowed to condense on the cooled substrate surface where it is polymerized by a radiation source. The process depends on the vapor pressure difference between liquid in the monomer source and liquid condensed on the surface of the cooled substrate. The film thickness is dependent on the temperature difference between the monomer reservoir and the substrate, and the time that is required to move the coated substrate from the evaporation chamber to the cure station. The method is suitable for forming very thin, uniform, pinhole-free, polymer coatings from a variety of monomers, having at least two olefinic groups per molecule, on a variety of substrates.