The invention is a product, comprising a substrate and a film that limits the transmission of water vapor comprising a polymer derived from one or more nonionic monomers polymerized in the presence of at least one nonionic surfactant and in the absence of ionic surfactants. The cloud temperature of the at least one nonionic surfactant is preferably less than the polymerization temperature. The nonionic surfactant is preferably an alkylene oxide (EO).sub.m(PO).sub.n adduct of an alkyl alcohol, alkylbenzene alcohol or dialkylbenzene alcohol, wherein (m+n).ltoreq.14. The invention includes a dispersion formed by polymerizing nonionic monomers at a polymerization temperature in the presence of at least one nonionic surfactant with a cloud temperature less than the polymerization temperature; a water vapor barrier composition; a film formed from the dispersion; a method of making the dispersion; a method of making a film; and a method of reducing the ability of water vapor to be transmitted with respect to a substrate.