The encapsulation of liquid substances and their controlled, targeted delivery is important to industry. However, the efficient encapsulation of liquid substances, especially volatile substances, has proven difficult. Although applications of encapsulation techniques are increasing year on year, there remain significant shortcomings and limitations. In particular, the encapsulation of volatile compounds is an area in which little progress has been made.
Particular problems are encountered in the encapsulation of perfume oils, which are volatile substances found in fine fragrances and other fragrance formulations. Although the use of microcapsules to encapsulate perfume oils has been proposed, fragrance formulations typically contain polar solvents such as ethanol in which the microcapsules are dispersed. These polar solvents can readily penetrate the wall of the microcapsules, causing the perfume oils to leach prematurely from the microcapsules. It would be desirable to provide microcapsules which enable perfume oils to be released in a controlled manner during use, e.g. by rupturing the microcapsules during normal human movement.
There is a need in the art for improved microcapsules for encapsulating liquid substances, especially microcapsules which exhibit an improved release profile. In particular, there is a need for microcapsules for encapsulating liquid substances such as perfume oils, wherein the microcapsules are substantially impermeable to polar solvents such as ethanol yet, at the same time, are capable of releasing their contents in a controlled manner during use. There is also a need for improved processes for the preparation of microcapsules.