lie above the mixture critical point as previously described. Generally,
depending on the flow rate and operating conditions such
as temperature and pressure, three regimes of liquid phase dispersion
are observed:(i)the dripping regime, in which the droplets are
formed at the outlet of the nozzle; (ii) the laminar regime, in which
the solvent was flowed smoothly and continuously before a breakup
zone where uniform size droplets are formed; (iii) the turbulent
regime, in which the jet surface becomes irregular [28] and the
resulting non-uniform droplets are formed as stretched and small
broken droplets. The ellipsoid–spheroid morphologies observed at
8 MPa suggested that the jet disintegration occurred at the laminar
regime. As the pressure increased to 10 and 12 MPa, the organic
solvent and CO2 interfacial surface tension decreased, the jet disintegration
entered the turbulent regime [28], resulting in irregular
jet surface. As a result, non-uniform flake-like and twisted leaf-like
particles were formed.