Determination of elastic constants of two-dimensional close-packed colloidal crystals

Abstract

We present a noncontact, accurate, and efficient methodology for determination of elastic constants in two- dimensional colloidal crystals via the calculation of the local strain fluctuation of particles. The hexagonally close- packed colloidal crystals form from microsized particles subjected to an alternating electric field. The elastic constants in the thermodynamic limit are obtained by the extrapolation of finite-size scaling of the elastic moduli as the functions of the frequency and field strength. It is found that the elastic constants in our system are larger than those in non- close-packed colloidal crystals reported before. This technique could be a rational method to study the elasticity of soft solids. © 2009 American Chemical Society.