Preparation of oil core/polyelectrolyte shell microcapsules by a coacervation method

摘要

Microcapsules with triallylamine-containing core surrounded by polyelectrolyte shell of controlled thickness were prepared via layer-by-layer assembly technology. First, isocyanate end-capped polyurethane was synthesized through the reaction of isophorone diisocyanate and poly(l,4-butylene adipate). Then, polyurea microcapsules containing triallylamine were prepared by the interfacial polymerization with branched polyethylenimine (PEI) as the water-phase macro-monomer and the prepared isocyanate end-capped polyurethane as the oil-phase macro-monomer. Finally, stable weak polyelectrolyte microcapsules were prepared by assembly of poly(acrylic acid)(PAA) and branehed PEI to build up polyelectrolyte multi-layers, and this was followed by glutaraldehyde mediated cross-linking to further increase the mechanical strength of the final capsules. Results showed that the obtained microcapsules were narrowly distributed in size and the mean diameter could be adjusted. This kind of capsule might be used to construct pressure-sensitive materials.