Latex polymers are frequently used as substitutes for solvent-borne coatings in environmental friendly technologies. However, the relationship between the copolymer composition and the latex film performance must be established. The preparation of a series of styrene-n-butyl acrylate latexes functionalized with different amounts of acrylic acid through semicontinuous emulsion polymerization is presented. In this work, latexes were employed to study the modification of the latex film properties by the addition of acrylic acid during the polymerization; mainly, the adhesion to the substrate, the water vapor permeability, and the electrical film resistance were examined. The most advantageous acrylic acid content was established by a balance of the tested properties. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 553-557, 2009