Ensemble effects in the detachment of floating microspheres

Somasundaran, P.; Varbonov, R.; Tchaliovska, S.; Nishkov, I.

doi:10.1016/0166-6622(92)80159-y

Cited by 5 publications

(2 citation statements)

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“…(i) In the case of flotation forces, the meniscus is due to the weight (incl. buoyancy force) of floating particles. − This force causes two-dimensional aggregation of floating particles; , its magnitude is proportional to R p 6 ( R p = particle radius). For that reason, the flotation capillary force strongly decreases with the decrease of R p and becomes immaterial for R p smaller than ca.…”

Section: Introductionmentioning

confidence: 99%

Capillary Forces between Colloidal Particles Confined in a Liquid Film: The Finite-Meniscus Problem

2001

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We consider a system made of two spherical particles confined between two fluid interfaces. The concept is illustrated in experiments with polystyrene micrometer-sized particles located between the two membranes of a bilamellar giant lipid vesicle. The particles locally separate the membranes and form a "Plateau border", which is filled with water. Experiments based on optical manipulation and dynamometry readily show that the particles attract each other. The interaction force is long-ranged (several particle radii) and goes through a maximum (about a piconewton) at finite particle separation. We propose a theory of the interaction, based on the linearized Laplace equation for the meniscus profile. The theory predicts that the meniscus around an isolated particle is finite, that is, bounded by a peripheral contact line, outside of which the film surfaces are equidistant. When two particles come near each other, their menisci overlap and fuse to form a unique meniscus with a new peripheral line. This is the source of the capillary interaction. The computation yields a characteristic nonmonotonic force-versus-distance profile, as experimentally observed with the latex particles. The computed profile quantitatively fits to the experimental data, with a single adjustable parameter, the bilayer tension. Other features of the interaction (hysteresis, dependence on particle size) are discussed. We find that the capillary attraction in general is strong enough to cause aggregation of the confined colloidal particles.

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Section: Introductionmentioning

confidence: 99%

Capillary Forces between Colloidal Particles Confined in a Liquid Film: The Finite-Meniscus Problem

2001

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“…Modeling the transport of a spherical particle across a liquid/liquid interface has been conducted by different investigators. − Here we present a robust method for calculating the contact angle based on the experimentally achieved force balance between the centrifugal, the buoyancy, and the capillary forces acting on a particle crossing the oil/water interface. The calculation diagram is presented in Figure .…”

Section: Calculation Of the Contact Angle Based On A Model Of A Solid...mentioning

confidence: 99%

A Novel Centrifugal Method for Wettability Characterization of Granulates

Swenson

Horváth‐Szabó

Abdallah

et al. 2011

Ind. Eng. Chem. Res.

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The minimum force needed for transporting glass microspheres across oil/water (O/W) interfaces was determined experimentally. From this data, the O/W contact angle was calculated with a mathematical model. First, the measured minimum centrifugal force was combined with a simplified model leading to an approximate contact angle. Then the results were refined by a numerical solution of the accurate mathematical model of particle transport through an oil/water interface. The contact angles calculated by the suggested approach were compared with the contact angles measured by goniometry on flat glass surfaces in the presence and absence of sodium dodecyl sulfate (SDS), Triton X-100, and Igepal CO-520 surfactants. The discrepancies were interpreted with the different surface chemistries/morphologies of glass microspheres and slides. The results show potential for this being a rapid screening method for chemical additives aimed at altering the wettability. This approach could be utilized in the oil and gas industry and especially to support enhanced oil recovery (EOR).

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