A method for coating the surface of a substrate composed of a hydrophobic polymer with a hydrophobic vinyl polymer. The method includes preparing a solution of the hydrophobic vinyl polymer in a polar nonaqueous solvent, such as 1-methyl-1-pyrrolidinone, in which the hydrophobic vinyl polymer is surface-active. The substrate then is treated with the solution under conditions sufficient to deposit the hydrophobic vinyl polymer on the substrate. The hydrophobic vinyl polymer may have readily hydrolyzable pendant groups which, upon hydrolysis thereof in an aqueous medium, will result in the formation of a hydrophilic vinyl polymer coating on the substrate. For example, the hydrophobic vinyl polymer may be poly(vinyl trifluoroacetate). Also provided are coated substrates, in which the substrate is a shaped article composed of a hydrophobic polymer. The shaped article may be, for example, a film, fiber, or nonwoven web.