Surface-Pressure Isotherms of Monolayers Formed by Microsize and Nanosize Particles

Abstract

The thermodynamic model of a 2D solution developed earlier for protein monolayers at liquid interfaces is generalized for monolayers composed of micro- and nanoparticles. Surface pressure isotherms of particle monolayers published in the literature for a wide range of particles sizes (between 75 microm and 7.5 nm) are described by the theoretical model with one modification. The calculations of surface pressure pi on area A provide satisfactory agreement with the experimental data. The theory also yields reasonable cross-sectional area values of the solvent molecule water in the range between 0.12 and 0.18 nm2, which is almost independent of particle size. Also, the area per particle in a closely packed monolayer obtained from the theory is quite realistic.

Solid-stabilized emulsions

“…Aveyard et al [4] were able to fit their isotherms with a model that takes into account the Coulombic repulsion between the charged particles through the oil phase. Fainerman et al [15] simply derived a model based on a 2D solution theory and were able to fit experimental data obtained with silanized particles. Both models are very general and could explain why the shape of the isotherms is highly robust even in the case of the particles mixtures.…”

Structural estimation of particle arrays at air–water interface based on silica particles with well‐defined and highly grafted poly(methyl methacrylate)

“…The most notable point is that the measured occupied area was much larger than the one expected from the hydrodynamic diameter of the polymer-modified particle. The onset area for the increasing surface pressure in the particle array system is generally several times larger than the area corresponding to the particle diameter [39]. Thus, this characteristic p-A isotherm suggests that PMMA chains were fully expanded at the air-water interface.…”

Composite interfacial layers containing micro-size and nano-size particles

“…Recently an equation of state for protein solutions was derived [101], the modification of which is suitable to describe Π-A isotherms of micro-and nanoparticles of different size. This equation was modified and successfully applied to monolayers formed by particles of different size [102].…”

“…The equation of state obtained in [102] is suitable for the description of particle monolayers at liquid interfaces:…”