Cobalt nanoparticles with tuned interaction potential: Towards worm- and chain-like aggregates

Abstract

Spin-coating of colloids is a versatile method in fabricating films of colloidal particles at a short span of time. Controlling key parameters like the rate of rotation, the initial concentration and the nature of the continuum phase is easy to perform experimentally. However, the effects of these parameters are not fully understood yet. To enhance the understanding of the coating process, we study the spin-coating of dilute magnetic colloids. The coating process is controlled externally by means of a magnetic field and we investigate its effects by studying the morphology of the dried coating obtained after the experiments. Morphological transitions are explained through the mean area and the number density of clusters, together with anisotropy properties. Further, we relate the occupation factor of clusters to the non-planarization conditions observed in this kind of experiments.