Micro-encapsulation has gained rapidly interest into a variety of industrial disciplines. One of the first industrial processes dates back to the 1930 years: the carbonless self copying paper: tiny micro-capsules filled with ink are fixed on the back side of the paper and crushed by the pencil when writing on the paper.
The majority of processes include a droplet separation step: either destined to form the shell, or to create the core form and size. In many cases the liquid phase is destined to solve the shell material for deposition around the core and is evaporated during the stabilization phase of the process. Other processes will favour gelling or crystallizing of the capsule wall.
Particle size requirements dictate frequently the choice of process and materials. Micro encapsulation is a physic-chemical process, total surface area determines most of the time the wall thickness and as such the resistance of the micro capsule in its final application.
There is a saying: micro encapsulation is at crossroads of art, science and technology. The right choice between process and chemistry, defining the processing conditions and parameters at a wide range of machines, is possible only for those with a sound scientific background, combined with a long time experience of trial and error.