Roles of aqueous additives in the mass transfer process of water molecules in water/oil/water double emulsion droplets

Abstract

Finding suitable aqueous additives to inhibit the mass transfer of water molecules in double emulsion droplets is beneficial for improving the surface quality of polymer shells. In this work, fluorobenzene/aqueous systems with polyvinyl alcohol (PVA) molecules and electrolyte ions were constructed by molecular dynamics simulation, which are typical water/oil (W/O) systems in actual fabrication processes of polymer shells. The interfacial mass transfer coefficients and equilibrium water solubility in fluorobenzene of various W/O systems were calculated by fitting the dissolution curves with a classical mass transfer model. The effects of polyvinyl alcohol additives on the diffusion process of water molecules at the fluorobenzene/water interface were investigated from the perspectives of thermodynamics and microscopic interface morphology. Furthermore, to avoid the inner surface defects of polymer shells caused by electrolyte ions osmosis, 1,3-butanediol molecules were proposed to replace ions as aqueous solutes, which also inhibited the diffusion of water molecules to fluorobenzene membrane.