(30a) Visualization of Spray Characteristics and Resulting Particles in Sas at Different Solute and Solvent Misciblities

A high-resolution imaging system was used to study the supercritical antisolvent (SAS) precipitation process. Polymers and copolymers with different miscibilities in a solvent were processed through SAS. The copolymers consist of the same components but in different ratios chosen to alter the miscibility of the solute in the solvent, thereby changing the CO₂ concentration at which the solute becomes supersaturated. These experiments allow similar solutes to be supersaturated by various CO₂ concentrations at the same operating parameters. Visualizations were obtained at various distances from the nozzle outlet to observe the spray characteristics at very high magnification levels. The resulting particles were analyzed using a scanning electron microscope. These experiments were performed to determine how the spray and resulting particles are affected by the miscibility of the solute in the solvent.