Principle
Microcapsules having a thermal release. A new approach to the fabrication of core shell capsules

The principle (see figure 1) is based on the hot production of an emulsion formed by oil droplets in an aqueous phase, followed by the synthesis of a rigid, brittle shell coating the droplets. This emulsion has two characteristics:

• water-oil interface stabilizers are solid particles (Pickering emulsions);

• oil characterized by its melting temperature T_f is solid at storage temperature and becomes liquid at use temperature. The melting of the oil is accompanied by a volumetric expansion that is sufficient to break the solid shell. Indeed, because of its rigid nature, the silica shell (silicon dioxide noted SiO₂) is too little deformable to take up the internal mechanical stress during melting.