Layer-by-layer deposition of clay and a polycation to control diffusive release from polyurea microcapsules

Polyurea microcapsules containing model organic fills were coated with clay and polycation layers to control diffusive release. This control process allows post-modification of the release rate without interfering with capsule formation. Microcapsules prepared by interfacial polyaddition of polymethylene polyphenyl isocyanate and diethylenetriamine were chosen as representative polyurea capsules having cationic surface charges. The …