English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Charged colloidal monolayers at the interface between water and air (or oil)are used in a large number of chemical, physical and biological applications.Although a considerable experimental and theoretical effort has been devoted inthe past few decades to investigate such monolayers, some of their fundamentalproperties are not yet fully understood. In this paper, we model chargedcolloidal monolayers as a continuum layer of finite thickness, with separatecharge distribution on the water and air sides. The electrostatic surfacefree-energy and surface pressure are calculated via the charging method andwithin the Debye-H{\"u}ckel approximation. We obtain the dependence of surfacepressure on several system parameters: the monolayer thickness, its distinctdielectric permittivity, and the ionic strength of the aqueous subphase. Thesurface pressure scaling with the area per particle, ${a}$, is found to bebetween ${a}^{-2}$ in the close-packing limit, and ${a}^{-5/2}$ in theloose-packing limit. In general, it is found that the surface-pressure isstrongly influenced by charges on the air-side of the colloids. However, whenthe larger charge resides on the water-side, a more subtle dependence on saltconcentration emerges. This corrects a common assumption that the charges onthe water-side can \textit{always} be neglected due to screening. Finally,using a single fit parameter, our theory is found to fit well the experimentaldata for strong to intermediate strength electrolytes. We postulate that ananomalous scaling of $a^{-3/2}$, recently observed in low ionic concentrations,cannot be accounted for within a linear theory, and its explanation requires afully-nonlinear analysis.

Surface Pressure of Charged Colloids at the Air/Water Interface