scholarly journals Particle and Particle-Surfactant Mixtures at Fluid Interfaces: Assembly, Morphology, and Rheological Description

2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Armando Maestro ◽  
Eva Santini ◽  
Dominika Zabiegaj ◽  
Sara Llamas ◽  
Francesca Ravera ◽  
...  
Keyword(s):  
Contact Angle ◽  
Equations Of State ◽  
Fluid Interfaces ◽  
Interfacial Behavior ◽  
Fluid Interface ◽  
Surfactant Mixtures ◽  
Interfacial Assembly ◽  
Shear Rheology ◽  
Properties Of Materials ◽  
Definition Of

We report here a review of particle-laden interfaces. We discuss the importance of the particle’s wettability, accounted for by the definition of a contact angle, on the attachment of particles to the fluid interface and how the contact angle is strongly affected by several physicochemical parameters. The different mechanisms of interfacial assembly are also addressed, being the adsorption and spreading the most widely used processes leading to the well-known adsorbed and spread layers, respectively. The different steps involved in the adsorption of the particles and the particle-surfactant mixtures from bulk to the interface are also discussed. We also include here the different equations of state provided so far to explain the interfacial behavior of the nanoparticles. Finally, we discuss the mechanical properties of the interfacial particle layers via dilatational and shear rheology. We emphasize along that section the importance of the shear rheology to know the intrinsic morphology of such particulate system and to understand how the flow-field-dependent evolution of the interfacial morphology might eventually affect some properties of materials such as foams and emulsions. We dedicated the last section to explaining the importance of the particulate interfacial systems in the stabilization of foams and emulsions.

scholarly journals β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 5. Adsorption Isotherm and Equation of State Revisited, Impact of pH

2021 ◽  
Vol 5 (1) ◽  
pp. 14
Author(s):  
Georgi G. Gochev ◽  
Volodymyr I. Kovalchuk ◽  
Eugene V. Aksenenko ◽  
Valentin B. Fainerman ◽  
Reinhard Miller
Keyword(s):  
Theoretical Description ◽  
Fluid Interfaces ◽  
Interfacial Behavior ◽  
Current State ◽  
Air Interface ◽  
Direct Measurements ◽  
Wide Range ◽  
Dilational Viscoelasticity ◽  
Parameter Values ◽  
Β Lactoglobulin

The theoretical description of the adsorption of proteins at liquid/fluid interfaces suffers from the inapplicability of classical formalisms, which soundly calls for the development of more complicated adsorption models. A Frumkin-type thermodynamic 2-d solution model that accounts for nonidealities of interface enthalpy and entropy was proposed about two decades ago and has been continuously developed in the course of comparisons with experimental data. In a previous paper we investigated the adsorption of the globular protein β-lactoglobulin at the water/air interface and used such a model to analyze the experimental isotherms of the surface pressure, Π(c), and the frequency-, f-, dependent surface dilational viscoelasticity modulus, E(c)f, in a wide range of protein concentrations, c, and at pH 7. However, the best fit between theory and experiment proposed in that paper appeared incompatible with new data on the surface excess, Γ, obtained from direct measurements with neutron reflectometry. Therefore, in this work, the same model is simultaneously applied to a larger set of experimental dependences, e.g., Π(c), Γ(c), E(Π)f, etc., with E-values measured strictly in the linear viscoelasticity regime. Despite this ambitious complication, a best global fit was elaborated using a single set of parameter values, which well describes all experimental dependencies, thus corroborating the validity of the chosen thermodynamic model. Furthermore, we applied the model in the same manner to experimental results obtained at pH 3 and pH 5 in order to explain the well-pronounced effect of pH on the interfacial behavior of β-lactoglobulin. The results revealed that the propensity of β-lactoglobulin globules to unfold upon adsorption and stretch at the interface decreases in the order pH 3 > pH 7 > pH 5, i.e., with decreasing protein net charge. Finally, we discuss advantages and limitations in the current state of the model.

scholarly journals In situ assessment of the contact angles of nanoparticles adsorbed at fluid interfaces by multiple angle of incidence ellipsometry

Soft Matter ◽  
2014 ◽  
Vol 10 (36) ◽  
pp. 6999-7007 ◽  
Author(s):  
Antonio Stocco ◽  
Ge Su ◽  
Maurizio Nobili ◽  
Martin In ◽  
Dayang Wang
Keyword(s):  
Surface Coverage ◽  
Contact Angles ◽  
Fluid Interfaces ◽  
Angle Of Incidence ◽  
Fluid Interface ◽  
Colloidal Interactions ◽  
In Situ Assessment

Contact angles and surface coverage of nanoparticles adsorbing at the fluid interface are assessed by ellipsometry. Results reveal the competition between wetting and colloidal interactions.

Continuum and Molecular Dynamics Studies of the Hydrodynamics of Colloids Straddling a Fluid Interface

2021 ◽  
Vol 54 (1) ◽  
Author(s):  
Charles Maldarelli ◽  
Nicole T. Donovan ◽  
Subramaniam Chembai Ganesh ◽  
Subhabrata Das ◽  
Joel Koplik
Keyword(s):  
Molecular Dynamics ◽  
Characteristic Size ◽  
Two Dimensions ◽  
Annual Review ◽  
Publication Date ◽  
Fluid Interfaces ◽  
Particle Interactions ◽  
Fluid Interface ◽  
Interfacial Energies ◽  
Multiple Particle

Colloid-sized particles (10 nm–10 μm in characteristic size) adsorb onto fluid interfaces, where they minimize their interfacial energy by straddling the surface, immersing themselves partly in each phase bounding the interface. The energy minimum achieved by relocation to the surface can be orders of magnitude greater than the thermal energy, effectively trapping the particles into monolayers, allowing them freedom only to translate and rotate along the surface. Particles adsorbed at interfaces are models for the understanding of the dynamics and assembly of particles in two dimensions and have broad technological applications, importantly in foam and emulsion science and in the bottom-up fabrication of new materials based on their monolayer assemblies. In this review, the hydrodynamics of the colloid motion along the surface is examined from both continuum and molecular dynamics frameworks. The interfacial energies of adsorbed particles is discussed first, followed by the hydrodynamics, starting with isolated particles followed by pairwise and multiple particle interactions. The effect of particle shape is emphasized, and the role played by the immersion depth and the surface rheology is discussed; experiments illustrating the applicability of the hydrodynamic studies are also examined. Expected final online publication date for the Annual Review of Fluid Mechanics, Volume 54 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Dependence of the Contact Angle on Adsorption at the Solid-Liquid Interface

2010 ◽  
Author(s):  
C. A. Ward
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Pressure Range ◽  
Line Tension ◽  
Liquid Interface ◽  
Fluid Interfaces ◽  
Phase Line ◽  
Three Phase ◽  
Solid Liquid Interface ◽  
Solid Liquid

A method for determining the surface tension of solid-fluid interfaces has been proposed. For a given temperature and fluid-solid combination, these surface tensions are expressed in terms of material properties that can be determined by measuring the amount of vapor adsorbed on the solid surface as a function of xV, the ratio of the vapor-phase pressure to the saturation-vapor pressure. The thermodynamic concept of pressure is shown to be in conflict with that of continuum mechanics, but is supported experimentally. This approach leads to the prediction that the contact angle, θ, can only exist in a narrow pressure range and that in this pressure range, the solid-vapor surface tension is constant and equal to the surface tension of the liquid-vapor interface, γLV. The surface tension of the solid-liquid interface, γSL, may be expressed in terms of measurable properties, γLV and θ: γSL = γLV(1 − cosθ). The value of θ is predicted to depend on both the pressure in the liquid at the three-phase, line x3L, and the three-phase line curvature, Ccl. We examine these predictions using sessile water droplets on a polished Cu surface, maintained in a closed, constant volume, isothermal container. The value of θ is found to depend on the adsorption at the solid-liquid interface, nSL = nSL(x3L,Ccl). The predicted value of θ is compared with that measured, and found to be in close agreement, but no effect of line tension is found.

Interfacial behavior between particle and matrix in a composite rubber material

2011 ◽  
Vol 20 (1-3) ◽  
pp. 29-33
Author(s):  
Bartolomeo Trentadue
Keyword(s):  
Tensile Specimen ◽  
Interfacial Behavior ◽  
Rubber Material ◽  
Contour Integrals ◽  
Surrounding Matrix ◽  
Final Output ◽  
Definition Of ◽  
Electronic Holography ◽  
Creep Loading ◽  
Principal Strains

AbstractElectronic holography moiré is applied to the measurement of interfacial deformation field between an embedded particle and its surrounding matrix in a non-homogeneous rubber material. A tensile specimen is subjected to creep loading. The loads are applied in steps and measurements are carried out at equal intervals of time. The final output is provided by the Holo-Moiré Strain Analyzer and gives the principal strains and their directions in the region of observation. A definition of adhesion as an experimental measurable quantity through the evaluation of contour integrals is introduced.

Contact angle of micro- and nanoparticles at fluid interfaces

2014 ◽  
Vol 19 (4) ◽  
pp. 355-367 ◽  
Author(s):  
Armando Maestro ◽  
Eduardo Guzmán ◽  
Francisco Ortega ◽  
Ramón G. Rubio
Keyword(s):  
Contact Angle ◽  
Fluid Interfaces
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