Surfactants and Microcapsule Formation

Abstract

Encapsulation procedures based upon complex coacervation and polymer/polymer incompatibility involve three-phase systems. The interfacial free energies (γIT) that exist in such systems determine whether or not encapsulation is successful. Since surfactants affect γ IT values, they can have a major effect on the success of these types of encapsulation procedures. An analysis of published γ IT data for a variety of three-phase systems indicates that the γIT values necessary for successful encapsulation are predictable. However, pronounced interfacial aging phenomena encountered in actual encapsulation systems complicates interpretation of the γ IT data. Examination of published studies of the behavior of three-phase systems suggests that surfactants can have both favorable and unfavorable effects on microcapsule quality, when quality is defined as the ability of a capsule to retain its encapsulated material.