Controlled transition of microcapsules from coil conformation to globule during the expansion of the pulse jet of nanoparticle suspension of TiO2 in supercritical (CO2) polyethylene glycol solution

摘要

The process of microencapsulation of titanium dioxide nanoparticles during the expansion of a supersonic jet of TiO2 suspension in a solution of polyethylene glycol (PEG 8000) in supercritical CO2 into a vacuum and background gas (helium) has been studied experimentally. The dependence of the position of the microcapsule transition point on the jet axis from the coil to a globular conformation on the temperature in the reactor and on the pressure of the background gas at different cosolvent concentrations has been established. A re-entrant (globule-coil) transition has been recorded at a greater distance from the nozzle exit than the point of collapse.