Abstract
Membrane emulsification using Shirasu-porous-glass (SPG) membranes is a novel method for preparing monodispersed emulsions. In this study, effects of interfacial tension, and viscosities of dispersed and continuous phases on
droplet formation were investigated using various surfactant concentrations and various dispersed and continuous
phases. Decane was pressurized into a stirring sodium dodecyl sulfate (SDS) aqueous solution in an interfacial tension range of 4.7 to 35.7 mN･m–1 through a SPG membrane with a mean pore diameter of 3.1μm, at a transmembrane pressure larger than capillary pressure. Under these conditions, monodispersed oil-in-water emulsions with a
mean droplet diameter of approximately 10μm were stably prepared. Oil-water interfacial tension barely affected the
resulting droplet diameter. In a system composed of decane containing liquid paraffin and SDS solution containing
polyethylene glycol, experimental results showed that the resulting droplet diameter increased with increasing waterphase viscosity, while droplet diameter decreased with increasing oil-phase viscosity. Droplet diameter decreased as
the ratio of oil-phase to water-phase viscosity increased. However, droplet diameter did not change in the case of a
constant viscosity ratio.
