Microflows, pore and matrix evolution in latex coatings

A latex coating begins as a layer of colloidal suspension of polymer particles that, upon drying of the layer, coalesce into a continuous film. The evolving arrangement and shape of the particles have for years been described as a succession of three stages: consolidation from suspension into a packing, compaction that deforms the packed spheres, and strength development by interdiffusion across interparticle contacts. In this thesis, the stages were studied as transformations of the porespace and the flows of liquid into and within it.;Geometric and physical insights drawn from sedimentology were applied to the growing porespace in ordered top-down consolidation of latex spheres. A unit of porespace, the bilayer, was shown to be crucial to connectivity and flows. Resistance-network representations were analyzed for the flow patterns into and within the bilayer. Two flow mechanisms were thereby discovered which might explain the prevalence of face-centered cubic packing in ordered latex and in consolidation of other colloidal dispersions.;Pore geometry and connectivity governs liquid flow in the porespace. In this thesis, the radii of pore throats were calculated as a function of pore volume exported during uniform compaction of ordered latex packing. To do this, the surfaces of deforming particles were approximated as constant-volume truncated spheres. The compactions studied were isotropic, unidirectional, and transverse-isotropic. The resistance-network analysis was repeated for partly compacted packings to show the effect of anisotropy on flow.;Images of latex particles fully deformed to polyhedra were simulated with a graphical algorithm developed for the software package Mathematica . Anisotropically compacted particles appear different from isotropically compacted ones. Simulated particles were compared to scanning electron micrograph images of fractured latex coatings and used to evaluate the coatings' anisotropy of compaction.;The results for uniform compaction were applied to transverse-isotropic compaction that is nonuniform with depth, which is a prerequisite of skinning that can slow drying and promote defects. A model of flow-controlled deformation was constructed to study pore narrowing and air invasion in a drying multilayer of latex. The results were incorporated into an account of the consolidation and compaction stages of latex film formation.