The Importance of Proper Anchoring of an Amphiphilic Dispersant for Colloidal Stability

Highly stable poly(methyl methacrylate) (PMMA) based microcapsule suspensions without excess dispersant are obtained via the solvent evaporation route using poly(methyl methacrylate)-block-poly(sodium methacrylate) or poly(methyl methacrylate)-block-poly(sodium acrylate) diblock copolymers as dispersant. The stable suspension is characterized by a high ζ-potential that does not change with time or after washing steps. It is indirectly proven on model PMMA surfaces using quartz crystal microbalance with dissipation monitoring that the PMMA block of the copolymer is embedded in the underlying PMMA microcapsule. Such anchoring of the dispersant is key for the good colloidal stability.