Morphological stabilization and KPZ scaling by electrochemically induced co-deposition of nanostructured NiW alloy films.

We have assessed the stabilizing role that induced co-deposition has in the growth of nanostructured NiW alloy films by electrodeposition on polished steel substrates, under pulsed galvanostatic conditions. We have compared the kinetic roughening properties of NiW films with those of Ni films deposited under the same conditions, as assessed by Atomic Force Microscopy. The surface morphologies of both systems are super-rough at short times, but differ at long times: while a cauliflower-like structure dominates for Ni, the surfaces of NiW films display a nodular morphology consistent with more stable, conformal growth, whose height fluctuations are in the Kardar-Parisi-Zhang universality class of rough two-dimensional interfaces.

Optimization of the surface properties of nanostructured Ni-W alloys on steel by a mixed silane layer.

Ni-W nanostructured coatings electrodeposited on steel by galvanostatic pulses were functionalized by tetraethoxysilane (TEOS) and octadecyltrichlorosilane (OTS) in a two-step procedure. A silica-rich layer is formed by the reaction of TEOS with the metal coating surface oxides, which allows a further reaction with OTS forming a hydrocarbon-silica outer network. This mixed silane layer provides hydrophobicity and improves the corrosion behavior of the Ni-W surface coatings without modifying their excellent mechanical properties.

Estimating diffusion coefficients of probe molecules into polyelectrolyte brushes by electrochemical impedance spectroscopy.

Molecular transport through thin polymer films has become a subject with a variety of challenges and opportunities for chemists, physicists, and material scientists in recent years. The diffusion of probe molecules in and out of macromolecular environments plays a major role in the response of polymer-based sensor materials or the design of time-released drug delivery systems. Obtaining an improved understanding of the relevant dynamic phenomena, like transport of molecular probes, in boundary layers represents a crucial step to develop a clearer picture of the molecular transport processes taking place at interfaces modified with macromolecular assemblies.