Nonionic surfactant-stabilised oil-in-water emulsions offer a potentially useful vehicle for transporting heavy crude oils from oilfields to refineries or distribution terminals. Prior to refining, separation of the oil from the emulsion is necessary. Previous studies have suggested that heating the emulsion is sufficient for destabilisation and recovery of the oil. The present work examines th...

Anyone who has enjoyed a glass of wine has undoubtedly noticed the regular pattern of liquid beads that fall along the inside of the glass, or 'tears of wine.' The phenomenon is the result of a flow against gravity along the liquid film on the glass, which is induced by an interfacial tension gradient. It is generally accepted that the interfacial tension gradient is due to a composition gradie...

The effect of copolymers on the breakup and coalescence of polybutadiene ~PB! drops in polydimethylsiloxane ~PDMS! is studied using a four-roll mill flow cell. Copolymers are produced at the interface by a reaction between functionalized homopolymers. They reduce the interfacial tension and thus enhance breakup; they also inhibit coalescence of drops. Under the conditions of our experiments, th...

A mesoscopic or coarse-grained approach is presented to study thermocapillary induced flows. An order parameter representation of a two-phase binary fluid is used in which the interfacial region separating the phases naturally occupies a transition zone of small width. The order parameter satisfies the Cahn-Hilliard equation with advective transport. A modified NavierStokes equation that incorp...

The ultralow interfacial tension of the two-liquid phase of a ternary system 1-propanol–n-heptane–water was determined with a pendant drop method using the axisymmetric drop shape analysis (ADSA) methodology. Because the two liquid phases of the ternary system are practically miscible at temperatures near the critical solution temperature, the drops are small and difficult to distinguish from t...

The interfacial tension (IFT) between aluminium and cryolite melts containing different salt additions (AlF3, NaF, Na2SO4) has been measured during electrolysis by the capillary depression method. The technique is based on the measurement of the capillary depression occurring when a capillary, which is moved vertically down through the molten salt layer, passes through the metal/salt interface....

Deformation and breakup of a viscous drop in a Bingham liquid is investigated numerically with a volume-of-fluid scheme. Initially, a spherical drop is placed between two moving parallel plates. For our parameters, the matrix liquid has yielded. The competing effects driving the motion are the shear and interfacial tension. When interfacial tension effects dominate, the drop evolves to a steady...

Recent experiments on imbibition in columnar geometries show interfacial fluctuations whose dynamic scaling is not compatible with the usual nonlocal model governed by surface tension that results from a macroscopic description. To explore this discrepancy, we exhaustively analyze numerical integrations of a phase-field model with dichotomic columnar disorder. We find that two distinct behavior...

We pursue a systematic statistical mechanics study of finite smectic stacks of semiflexible manifolds bounded by interfaces under tension. We address, by analytic calculations and Monte Carlo simulations, the effects of the surface tension on smectic interlayer distances. We use our theoretical results to elucidate the so called vapor pressure paradox (VPP) in multilamellar membrane phases and ...

We investigate interfacial properties between two highly incompatible polymers of different stiffness. The extensive Monte Carlo simulations of the binary polymer melt yield detailed interfacial profiles and the interfacial tension via an analysis of capillary fluctuations. We extract an effective Flory-Huggins parameter from the simulations, which is used in self-consistent field calculations....