Monomolecular Films. The Liquid-Liquid Interface and the Stability of Emulsions

Fischer, Earl K.; Harkins, William D.

doi:10.1021/j150331a006

Cited by 37 publications

(12 citation statements)

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“…However, early work on liquid interfaces was mostly non-electrochemical, focusing on extraction processes, salting-out in ion solvent extraction, measurements of physical properties such as interfacial tension, and physiological studies on model membranes [94][95][96][97][98][99][100][101][102] . Systematic electrochemical treatment did not begin until the late 1970's when Koryta et al 103 demonstrated that the liquid/liquid interface lends itself to the same formalism as a solution/ metal interface and that similar, if not identical, experimental methodology could be used.…”

Section: When Nernstmentioning

confidence: 99%

Interface Between Two Immiscible Liquid Electrolytes: A Review

Vanýsek

Ramírez²

2008

J. Chil. Chem. Soc.

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Section: When Nernstmentioning

confidence: 99%

Interface Between Two Immiscible Liquid Electrolytes: A Review

Vanýsek

Ramírez²

2008

J. Chil. Chem. Soc.

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“…To do so, molecular interfacial structural information needs to be correlated with droplet stability data. This is typically done − by correlating surface structural data from extended planar interfaces, such as that gathered from X-ray, − neutron scattering/reflection, , and sum frequency generation (SFG) − studies, to stability data of droplets made of the same chemicals as the planar systems. These studies show that surfactants lower the interfacial energy of macroscopic planar interfaces by forming a densely packed (geometric) monolayer.…”

mentioning

confidence: 99%

The Molecular Mechanism of Nanodroplet Stability

et al. 2017

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Mixtures of nano- and microscopic oil droplets in water have recently been rediscovered as miniature reaction vessels in microfluidic environments and are important constituents of many environmental systems, food, personal care, and medical products. The oil nanodroplet/water interface stabilized by surfactants determines the physicochemical properties of the droplets. Surfactants are thought to stabilize nanodroplets by forming densely packed monolayers that shield the oil phase from the water. This idea has been inferred from droplet stability measurements in combination with molecular structural data obtained from extended planar interfaces. Here, we present a molecular level investigation of the surface structure and stability of nanodroplets and show that the surface structure of nanodroplets is significantly different from that of extended planar interfaces. Charged surfactants form monolayers that are more than 1 order of magnitude more dilute than geometrically packed ones, and there is no experimental correlation between stability and surfactant surface density. Moreover, dilute negatively charged surfactant monolayers produce more stable nanodroplets than dilute positively charged and dense geometrically packed neutral surfactant monolayers. Droplet stability is found to depend on the relative cooperativity between charge-charge, charge-dipole, and hydrogen-bonding interactions. The difference between extended planar interfaces and nanoscale interfaces stems from a difference in the thermally averaged total charge-charge interactions in the two systems. Low dielectric oil droplets with a size smaller than the Debye length in oil permit repulsive interactions between like charges from opposing interfaces in small droplets. This behavior is generic and extends up to the micrometer length scale.

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“…Sample Size-Since most emulsions have broad droplet size distributions, many investigators count several thousand droplets per sample to obtain reliable average droplet sizes (11)(12)(13). The number of droplets that must be counted to obtain estimates of the mean diameter with a predetermined accuracy is discussed.…”

Section: Resultsmentioning

confidence: 99%