We studied the interfacial tension between coexisting phases of aqueous solutions of dextran and polyethylene glycol. First, we characterized the phase diagram of the system and located the binodal. Second, the tie lines between the coexisting phases were determined using a method that only requires measuring the density of the coexisting phases. The interfacial tension was then measured by a s...

Interfacial tension and viscosity of a liquid play an important role in microfluidic systems. In this study, temperature dependence of surface tension, interfacial tension and viscosity of a nanofluid are investigated for its applicability in droplet-based microfluidics. Experimental results show that nanofluid having TiO2 nanoparticles of 15 nm diameters in deionized water exhibit substantiall...

The dependence of the interfacial tension of a lipid membrane on the pH of the aqueous solution has been studied. Interfacial tension measurements of phosphatidylethanolamine (PE) were carried out. A theoretical equation is derived to describe this dependence in the whole pH range. A maximum corresponding to the isoelectric point appears both in the theoretical equation and in the experimental ...

A theory is presented to account for the increase in surface tension of water in the presence of electrolyte. Unlike the original “grandcanonical” calculation of Onsager and Samaras, which relied on the Gibbs adsorption isotherm and lead to a result which could only be expressed as an infinite series, our approach is “canonical” and produces an analytic formula for the excess surface tension. F...

Abstract Hydraulic fracturing is often used in unconventional shale reservoirs, and 50%–95% of the injected hydraulic fluid remains formation due to capillary effect. This phenomenon has been observed Montney formation, Canada, where flowback water recovery generally less than 25%. Surfactant one additives for reducing surface tension forces facilitate recovery. loss adsorption by reservoir roc...

The dark-field microscope may be used to observe directly the characteristics of composite films. The liquid phases, one or both of them containing suspended solid particles as test objects (in these experiments bacteria were used), are spread between slide and cover-glass and examined with any desired lenses. The liquid-liquid interfaces appear as bright lines and the solid particles as shinin...

The influence of molecular weight asymmetry across an interface on the transient behavior of the interfacial tension is investigated for two different polymer combinations, polybutadiene (PBD)/polydimethylsiloxane (PDMS) and polybutene (PB)/PDMS. This choice ensures a minor diffuse interface using the first combination and a very diffuse interface in the latter case. Measurements of the interfa...

Water-oil relative permeability characterizes two-phase flow and displacement processes, and its functional form is difficult to determine in a particular reservoir study. Adding various chemical agents into the displacing aqueous phase during alkaline-surfactant-polymer combination chemical flooding in oil production significantly changes interfacial tension (σ) on water-oil interfaces, and al...

We demonstrate the influence of molecular weight and molecular weight asymmetry across an interface on the transient behavior of the interfacial tension. The interfacial tension was measured as a function of time for a range of polymer combinations with a broad range of interfacial properties using a pendant/sessile drop apparatus. The results show that neglecting mutual solubility, assumed to ...

Highly monodisperse poly(N-isopropylacrylamide), PNiPAM, microgels were prepared by the conventional radical polymerization of NiPAM in the presence of dimethylamino ethyl methacrylate (DMAEMA) monomers at various concentrations. The effect of DMAEMA on the polymerization of PNiPAM microgels was examined at constant initiator (V50) and cross-linker (MBA) concentrations. The presence of DMAEMA i...