4. PGSS, microencapsulation and other processes

4.1 PGSS process

A gas under pressure can be solubilized in a liquid in large quantities: this is the property used here. A dense gas, most commonly CO ₂ , is dissolved in a liquid in a first autoclave. This liquid can be a solution, a suspension or even a polymer melt.

The resulting gas-saturated solution is sent through a nozzle into an expansion chamber (figure 6 ). Particle generation takes place during depressurization, and the particles formed are then collected in the expansion autoclave. During depressurization, CO ₂ can also act as an aerosolization activator.

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