There have been previously reported attempts at using supercritical fluids to coat particles, but, to the authors’ knowledge, none using the approach outlined above. Kim et al. [19] and Mishima et al. [20] used RESS to encapsulate active substances in polymer particles by dissolving both components in supercritical-CO2 and co-precipitating the mixture. Bertucco and Vaccaro [21] used anti-solvent methods for encapsulation from a suspension of particles in conventional solvents, while composite particles have also been produced by the supercritical anti-solvent technique [22] and [23]. Wang et al. [24] used the RESS technique to precipitate PVC covinyl acetate and hydroxypropyl cellulose onto 315 and 500 μm glass spheres placed in a collector vessel held at a pressure and temperature intermediate between supercritical and ambient. They also added acetone to the CO2 in order to enhance solubility of the polymer. The coating quality varied from smooth, when the polymer contacted the glass surface in a liquid state, to particulate, when precipitation occurred prior to contact. Tsutsumi et al. [25] and Wang et al. [26] expanded a RESS jet through a nozzle into a bed fluidized with air, and deposited a smooth paraffin coating onto 56 μm catalyst particles and 1 μm SiO2, respectively. Schreiber et al. [27] and [28] coated various particles with paraffins by expanding supercritical solutions into a bed at high pressure fluidized with carbon dioxide. Krober and Teipel [29] coated glass beads with stearyl alcohol in a similar manner.