Encapsulation of Clay Platelets inside Latex Particles

We present our recent attempts in encapsulating clay platelets inside latex particles by emulsion polymerization. Face modification of clay platelets by cationic exchange has been shown to be insufficient for clay encapsulation, leading to armored latex particles. Successful encapsulation of covalently edge-modified clay platelets was achieved via surfactant-free, starved-feed emulsion polymerization. With cryo-TEM and SEM we showed that small Laponite platelets were encapsulated inside spherical latex particles, whereas larger montmorillonite platelets were encapsulated inside dumbbell- like or snowman-like non-spherical latex particles. Covalent bonding of polymerizable groups to the clay platelets proves to be essential for the successful clay encapsulation.