Two dimensional colloidal assembly under an alternating electric field: From introduction to structure

Abstract

The lateral assembly of charged, monodispersed colloidal particles into two dimensional (2D) ordered structures in the presence of alternating current electric (AC) field has evoked much interest in the past two decades both experimentally and theoretically. In our study, systematic investigations of the assembly mechanisms under an AC field were performed by tuning frequency, field strength, salt concentration, particle size, and temperature etc. The system is also used as model system to study fundamental physics such as 2D phase transition, and kinetics of colloidal crystallization etc. Based on the understanding obtained, we further explored the implications for fabrication of colloidal crystal with tunable lattice spacing over a wide range. Such tunable colloidal system might find a variety of applications including switchable photonic devices and colloidal nanolithography.