ANNEALING EFFECTS ON THE SURFACE-STRUCTURE OF LATEX FILMS STUDIED BY ATOMIC FORCE MICROSCOPY

The effect of annealing on latex film surface structure was followed by atomic force microscopy. The films were prepared from poly(butyl methacrylate) particles (PBMA, d = 337 nm) prepared by surfactant-free emulsion polymerization. The film surfaces were highly ordered, consistent with face-centered cubic packing in the film interior, and each particle maintained a truncated spherical shape. The peak-to-valley distance DELTAz was monitored as a function of annealing time. From DELTAz, the remaining surface per particle was calculated. With the aid of a simple diffusion model, we conclude from these data that polymer chains near the latex surface diffuse much faster than those within the film.