The friction coefficient of the sulphur-prevulcanized natural rubber (SPNR) film could be effectively reduced by deposition of poly(methyl methacrylate) (PMMA) particles. The nanoscale surface roughness of rubber, determined by atomic force microscope, was directly proportional to the particle size of PMMA particle at 12% surface coverage (Cs). The %Cs and surface roughness of the modified SPNR increased, while the friction coefficient decreased, with increasing PMMA latex concentration and immersion time. By using a mixture of latexes having both large and small sizes, the increase in the amount of small particles resulted in the better distribution of large particles deposited on the rubber surface. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115:3680-3686, 2010