Characterization of latex blend films by atomic force microscopy

Analysis of latex blend films, made possible by TappingMode(TM) atomic force microscopy, has provided insight into the interaction properties of hard and soft latex particles. Looked at in isolation, the hard latex forms a cracked and opaque him with no detectable particle deformation, while the soft latex coalesces into a transparent coating showing small domains with face-centred-cubic arrays. In blends where the soft component is present in amounts greater than 40% by volume, smoothed bumps are observed which appear larger than either the hard or soft particles alone. The smoothness of each bump, supported by other evidence, suggests that the soft particles have coalesced into a virtual continuum at the surface, while the overall surface unevenness is thought to be indicative of underlying hard particles. We interpret the submersion of the hard particles as arising because of the lower surface energy of the soft polymer. Copyright (C) 1996 Elsevier Science Ltd.