Morphology Of Porous Films Research Articles

Porous metallic films fabricated by self-assembly of gold nanoparticles

Morphology of porous films prepared by self-organization of Au nanoparticles capped with 1-dodecanethiol was investigated as a function of the solvent used and the solution concentration. The pores were formed due to water droplet condensation. The formation of the pore arrays was strongly dependent on the solvent used. Under suitable experimental conditions, the gold nanoparticle films with hexagonally packed micropores can be fabricated from chloroform solutions. The experimental conditions affecting pore formation and pore size regularity are discussed.

The use of impedance spectroscopy and optical reflection spectroscopy to study modified aluminium surfaces

Porous-type anodic oxide Al films were investigated by means of two non-destructive, in situ applicable analysis techniques, electrochemical impedance spectroscopy (EIS) and spectroscopic ellipsometry (SE). The porous part of the porous film cannot be characterized with EIS measurements in aqueous solutions due to short-circuiting of the porous oxide by the electrolyte in the pores. By introducing an optical model which matches previous TEM investigations it is shown that SE characterizes the porous film morphology, including the porous part and the barrier part thicknesses, porosity and film-substrate interface roughness throughout the entire growth process. SE also allows us to determine the change in growth rate for films formed at increasing current density.

ChemInform Abstract: THE KINETICS OF SILVER BROMIDE FILM FORMATION ON THE SILVER ANODE

AbstractDie anodische potentiodynamische Bildung von AgBr‐Filmen auf einer rotierenden Ag‐Elektrode (rde) wurde in wäßrigen Bf‐Lösungen untersucht.

The kinetics of silver bromide film formation on the silver anode

The anodic potentiodynamic formation of an AgBr film on an Ag rotating disc electrode was studied in aqueous bromide solutions. As the electron transfer step (1) is intrinsically fast, ▪ and as the film remains porous throughout its growth, the rate of film growth is limited by physical parameters such as ionic diffusion and migration in the solution. The anodic E/ I curves for AgBr film formation were calculated quantitatively by computer on the basis of the following model of film growth. Film formation occurs initially by the nucleation of islands of film to a critical thickness, and then these islands spread laterally until only small pores remain between them. As these pores become small, the resistance of the solution within them becomes rate limiting (at the anodic current peak). After the peak, the concentration of bromide ions at the pore base falls to zero and current is then controlled by the diffusion of bromide ions into the lengthening pores of the film. This lateral spreading mechanism and the subsequent retention of the porous film morphology has been substantiated by comprehensive Scanning Electron Microscope investigations.