Low temperature transmission electron microscopy and differential scanning calorimetry characterization of latexes stabilized with surface active block oligomers

Abstract

The spatial distribution of a short-chain amphiphilic diblock copolymer (i.e. block oligomer), used as an emulsifier during the preparation of a latex, is determined by low temperature transmission electron microscopy and differential scanning calorimetry (d.s.c.). The main question is whether intermixing of the amphiphilic block oligomer and latex core materials actually takes place to a significant extent. Electron microscopy gives a clear indication that a surfactant-rich layer exists in all latex samples examined. At very high surfactant concentration (>6%, not typically used in commercial latexes), electron beam radiation damage reveals the presence of a surfactant gradient from the particle surface to its core. These results are in good agreement with our d.s.c. data. © 1992.