Preparation of double layered shell microparticles containing an acid dye by a melt dispersion–coacervation technique

Two types of microparticles with a double layered shell containing an acid dye were prepared by using a melt dispersion–coacervation process. The surface morphology and the composition of the microcapsules were investigated using scanning electron microscope (SEM), and Fourier-transform infrared spectroscope (FTIR) respectively. The results showed that the loading content and morphologies strongly depend on the composition, the protective colloid, as well as on the outer polymeric shell and the way the solvent solubilizes it. The thermo-physical properties strongly depend on the nature of the core content and the synthesis conditions. Factors affecting the release performance of the microcapsules were investigated and the results are presented in this paper.