2. Principle

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 SiO ₂ ) is too little deformable to...