ATOMIC FORCE MICROSCOPY STUDY OF LATEX FILM FORMATION

Atomic force microscopy (AFM) images are reported for the surfaces of poly(butyl methacrylate) (PBMA) latex films. Films (30-mu-m thick) prepared by casting onto atomically smooth mica from surfactant-free latex dispersions show long-range periodic order consistent with face-centered cubic packing. Spin-coated films exhibit an open structure composed of particle clusters. Each cluster is highly ordered, but the ordering extends only over 10 or so particles. When the cast films are annealed (6 h, 70-degrees-C), particle-size holes appear in the film surface. We expect that these occur through relaxation of internal defects which allow individual particles to fall from the surface layer into an internal void.