Surfactant-mediated growth of nonequilibrium interfaces

Surfactant induced symmetric and thermally stable interfaces in Cu/Co multilayers

In this work we studied Ag surfactant induced growth of Cu/Co multilayers. The Cu/Co multilayers were deposited using Ag surfactant by the ion beam sputtering technique. It was found that Ag surfactant balances the asymmetry between the surface free energies of Cu and Co. As a result, the Co-on-Cu and Cu-on-Co interfaces become sharp and symmetric and thereby improve the thermal stability of the multilayer. On the basis of obtained results, a mechanism leading to symmetric and stable interfaces in Cu/Co multilayers is discussed.

Kinetic roughening and pinning of two coupled interfaces in disordered media

We studied the kinetic roughening dynamic of two coupled interfaces formed in paper wetting experiments at low evaporation rate. We observed three different regimes of impregnation in which kinetic roughening dynamics of coupled precursor and main fronts belong to different universality classes; nevertheless both interfaces are pinned in the same configuration. Reported experimental observations provide a novel insight into the nature of kinetic roughening phenomena occurring in the vast variety of systems far from equilibrium.

Protein-induced morphological transitions in KCl crystal growth

We investigated the formation of KCl crystals on a glass surface by phase contrast, fluorescent, and atomic force microscopy on the micrometer scale and observed interesting morphological transitions as a function of the experimental conditions. The presence of proteins in the solution from which the salt crystals grow during the drying up leads to complex microscopic patterns of crystals, some of which are analogous to those commonly observed on the macroscopic scale. We tested the effect of tubulin, FITC-labeled albumin, and IgG on the morphology of crystals grown either slowly or fast. A rich variety of protein-specific and concentration-dependent morphologies was found and described by a morphological diagram. We give a phenomenological interpretation, which can explain the growth of complex patterns. Fluorescent images prove that a protein layer covers the surface of the KCl structures. We propose that this layer reduces the anisotropy of the effective surface tension during growth. The tip splitting fractal regime is attributed to the decrease of anisotropy. Further possible mechanisms, which can cause a morphological transition, are also discussed. We found elongated saw-toothed crystals induced by proteins, especially IgG, and identified their structure.