Por João Cabral (Department of Chemical Engineering, Imperial College London, United Kingdom).
Motivated by spray drying approaches in the manufacturing of polymer particles and composites, we discuss experiments investigating the mechanism and kinetics of particle formation by controlled solvent extraction and evaporation of polymer solution droplets. We employ microfluidics and acoustic levitation to precisely handle the polymer droplets in controlled environments, focusing on the predictive design of particles and capsules with prescribed dimensions, shape, porosity, microstructure and function. We will discuss coupling of scattering approaches, such as small angle neutron and X-ray scattering (SANS/SAXS), and spectroscopy (and imaging) to elucidate the phase behaviour of formulations as well as investigate out-of-equilibrium properties under processing conditions with high spatio-temporal resolution. The current potential and limitations of these methods will be reviewed. Finally, we discuss a fundamental theoretical problem of polymer-polymer demixing and consequences for the design of nano and microstructured polymeric particles and capsules.
