(475n) Effect of Particulate Surfactant on Stability of the W/O Dispersion and Microencapsulation of Water

Microencapsulation of water (liquid phase) have been applied in such various fields as information and recording materials, cosmetics, paintings, medical materials, etc. But microcapsules containing water have problems such as low microencpasulation efficiency, caused by the escape of water in the microencapsulation process, and the leakage or the high release rate from microcapsules in use. To prevent the leakage of water before and after the microencapsulation process, it was investigated how a particulate surfactant affected the dispersion stability of the W/O and W/O/W dispersions in the microencapsulation process and the permeability of water through microcapsule shell. The more superior functions could be given to the microcapsules by using another solid powder with the other physical properties. In the experiment, an affinity of solid powder to the liquid-liquid interface, which affects adhesion state of solid powder, was stepwise changed by treating a silane coupling agent to prepare partclulate surfactants. The W/O/W dispersion was prepared using particulate surfactant prepared thus to microencapsulate water by in-situ polymerization. Microcapsules were found to have the structure that the outer and inner interfaces were covered with solid powders and water was included inside. The characteristics of microcapsules such as inner structure, mean diameter and water content were strongly affected by the affinity of particulate surfactant.