Micromechanics of elastic buckling of a colloidal polymer layer on a soft substrate: Experiment and theory

Abstract

We study the buckling instability of a colloidal particle layer adhered to an elastic substrate using an integrated experimental and theoretical approach. Experiments using monodisperse colloid-scale spherical particles made of polystyrene and silica, show that the wavelength of the initial (critical) buckling mode is independent of particle modulus and linearly dependent on particle radius - in contradiction with the predictions of the prevailing continuum model. We developed a granular model of the particle layer using structural mechanics techniques. The granular model predicts the observed wavelength of the initial, critical buckling mode within the estimated range of parameter values fo..