POLYMER COLLOID MORPHOLOGY STUDIED BY FREEZE-FRACTURE ELECTRON-MICROSCOPY

The technique of freeze-fracture electron microscopy has been applied to study the morphology of poly (methyl methacrylate) and polystyrene polymer colloid particles. Both aqueous emulsion-polymerized and nonaqueous dispersion-polymerized particles have been examined. We distinguish essentially two types of fracture patterns. One is composed of irregularly organized globules; the other has a well-developed structure with radiant lines directed from the center to the surface of the particles. The fracture pattern does not seem to be simply a material property of the polymer, and the polymerization medium is not the determining factor. We believe that the fracture pattern is characteristic of polymer particle growth mechanism. © 1990, American Chemical Society. All rights reserved.