Abstract
Alan R. Denton: „Melting of Dipolar Colloidal Crystals in an External Field”
North Dakota State University, USA
Suspensions of dipolar colloidal particles have attracted recent interest for their tunable materials properties and potential applications as ferrofluids, storage media, and display devices. Modern synthesis techniques enable fabrication of microspheres with permanent or induced electric or magnetic dipoles. Directional interactions between dipolar particles favour complex chain- and ringlike structures, observed in experiments and simulations. External fields that couple to the dipoles compete with interparticle interactions and can modify thermodynamic phase behaviour. After a brief introduction to dipolar colloids, I will describe an ongoing simulation study of melting in quasi-two-dimensional monolayers, in which the dipoles can rotate in three dimensions. A uniform external field, applied perpendicular to the monolayer, stabilizes a crystalline monolayer against melting. Spatially varying fields can produce high-resolution patterns in monolayers of bicoloured particles -- a scaled-down version of current electronic-ink display technology.