Buckling of a monolayer of plate-like particles trapped at a fluid-fluid interface

TL;DR

This study experimentally investigates the buckling behavior of monolayers of rigid, plate-like particles at fluid interfaces under compression, developing a theoretical model that links buckling wavelength to particle size, with implications for nanomaterial interfacial rheology.

Contribution

It introduces a combined experimental and theoretical analysis of buckling in monolayers of plate-like particles, highlighting a different scaling law from spherical particles and modeling the effect of bending rigidity.

Findings

Buckling wavelength is on the order of particle size.

Theoretical model matches experimental buckling data.

Bending rigidity influences buckling behavior.

Abstract

Particles trapped at a fluid-fluid interface by capillary forces can form a monolayer that jams and buckles when subject to uni-axial compression. Here we investigate experimentally the buckling mechanics of monolayers of millimeter-sized rigid plates trapped at a planar fluid-fluid interface subject to uni-axial compression in a Langmuir trough. We quantified the buckling wavelength and the associated force on the trough barriers as a function of the degree of compression. To explain the observed buckling wavelength and forces in the two-dimensional monolayer, we consider a simplified system composed of a linear chain of plate-like particles. The chain system enables us to build a theoretical model which is then compared to the two-dimensional monolayer data. Both the experiments and analytical model show that the wavelength of buckling of a monolayer of plate-like particles is of the order of the particle size, a different scaling from the one reported for monolayers of spheres. A simple model of buckling surface pressure is also proposed, and an analysis of the effect of the bending rigidity resulting from a small overlap between nanosheet particles is presented. These results can be applied to the modeling of the interfacial rheology and buckling dynamics of interfacial layers of 2D nanomaterials.