Engineering polymeric composite particles by emulsion-templating: Thermodynamics versus kinetics

We investigated the important factors that control the structure of polymeric particles fabricated from emulsion templates. We found that the most energetically stable structure predicted by interfacial energy analysis is not always achieved. The slow dynamics due to an increase in the viscosity of the emulsion phases prevents the polymeric particles from achieving their equilibrium structure. We devised a novel strategy to remove this kinetic barrier, thus achieving the expected equilibrium structure. By considering both the thermodynamic and kinetic aspects during the droplet evolution process, a spectrum of final particle structures can be manipulated in a controlled manner. Our work will enable particle engineering for applications including drug delivery, biomimetic vesicles and photonics.