In the course of cationic emulsion polymerization

octamethylcyclotetrasiloxane (D4) is first emulsified into "transition particles" with bigger diameters

on the surface of which the ring-opening reaction of D4 and the addition of D4 to OH-ended siloxanes take place. The particles are then transformed into stable emulsion particles are transformed into stable emulsion particles with extremely small and uniform particle size. The condensation of OH-ends of the polydimethylsiloxanes proceeds predominantly in the emulsion particles.