Increasing environmental concerns and regulations are the major driving forces for the development of waterborne pressure-sensitive adhesives. This article reported the synthesis of a series of poly[(n-butyl acrylate)-co-(acrylic acid)] latexes with different particle sizes using a semibatch emulsion polymerization process. By changing the levels of surfactant (Aerosol Series) at the seed stage, the z-average particle diameters (d(z)s) measured with dynamic light scattering varied from 124 to 366 rim. The polymerizations proceeded under monomer-starved conditions, and the values of d(z) measured for samples removed during the polymerizations were consistent with theoretical prediction for particle growth spherically without the secondary nucleation. The gel contents of the polymers were determined by Soxhlet extraction, and the molecular parameters were Characterized by gel permeation chromatography and dynamic mechanical thermal analysis. The adhesive properties, loop tack, peel force, and shear resistance were measured according to the Federation Internationale des Fabricants, et Transformateurs d'Adhesifs et Thermocollants sur Papiers et Autres Supports (FINAT) test methods. The results were reported and correlated with the latex particle size and molecular parameters. The spatial architecture of gel domains in the dry film and the molecular connectivity between those gel domains play an important role in controlling its adhesive properties. (c) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 3030-3040, 2009