Publication 581

Laboratoire de Chimie des Polymères (UMR 7610 associée au CNRS), Université Pierre et Marie Curie, Paris 6, Case 185, 4, Place Jussieu, 75252 Paris Cedex 05, France, Laboratoire d'Electrochimie Moléculaire (UMR 7591 associée au CNRS), Université René Diderot, Paris 7, 2, Place Jussieu, 75251, Paris Cedex 05, France, and Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada

Poly(2-ethylhexyl methacrylate)-based latex particles were synthesized with an acetal-functionalized methacrylamide comonomer. The acetal function is stable at alkaline pH but can be deprotected under acidic conditions to form an intermediate that can undergo acid-catalyzed self-condensation to introduce cross-links into the polymer under ambient conditions. Studies of the kinetics of hydrolysis of the acetal groups showed that the hydrolysis occurred much faster than the subsequent self-condensation reaction. The evolution with time of the cross-link density and the film morphology were monitored as a function of pH and of functional comonomer content for films formed from acidified latex dispersions. Energy transfer experiments were used to follow the rate of polymer diffusion across the interparticle boundaries in the film, in competition with the cross-linking reaction. These experiments showed that under ambient conditions, the major contributor to polymer diffusion was the lowest molecular weight components of the latex polymer. These chains ultimately underwent reaction to become incorporated into the polymer network, yielding films with reasonable tensile properties and good solvent resistance. When the temperature was increased, the extent of mixing due to polymer diffusion increased, but remained incomplete when the competing chemical reaction was fast.