Effect of Staining on Latex Particle Size Examined by Electron Microscopy

Abstract

Electron microscopy has been an invaluble tool to the study of polymer morphology, especially latex particles, microphase-separated block copolymers, and polymer blends. However, in order to examine these materials in an electron microscope, the sample often needs to be stained to heighten contrast between locales of different composition in the specimen. Staining usually has the following advantages: heightened contrast; higher polymer glass transition temperature Tg; lowered charging; and reduced radiation damage. However, staining can also introduce artifact. It is reported that the latex particle size is raised and the polybutadiene “sphere” in block copolymers is lowered after staining. This indicates that the staining process may be complex.Recently, low voltage field emission scanning electron microscopy (LVFESEM), especially high-resolution backscattered electron imaging produced with staining, has been used to study latex film formation, latex particle deformation and adhesion on substrates, latex particle deformation, distribution and binding in paper coatings.