Rhamnolipid biosurfactant complexation of rare earth elements.

Rare earth elements (REE) are vital for modern technologies and considered critical materials. This study investigated monorhamnolipid biosurfactant interactions with REE as the basis for REE recovery technology. Conditional stability constants (log β), measured using a resin-based ion exchange method, are reported for 16 REE and metals.

Evaporative deposition patterns of bacteria from a sessile drop: effect of changes in surface wettability due to exposure to a laboratory atmosphere.

Evaporative deposition from a sessile drop is a simple and appealing way to deposit materials on a surface. In this work, we deposit living, motile colloidal particles (bacteria) on mica from drops of aqueous solution. We show for the first time that it is possible to produce a continuous variation in the deposition pattern from ring deposits to cellular pattern deposits by incremental changes in surface wettability which we achieve by timed exposure of the mica surface to the atmosphere.

Measurements of the thickness compressibility of an n-octadecyltriethoxysilane monolayer self-assembled on mica.

The surface forces apparatus technique and the Johnson-Kendall-Roberts theory were used to study the elastic properties of an n-octadecyltriethoxysilane self-assembled monolayer (OTE-SAM) on both untreated and plasma-treated mica. Our aim was to measure the thickness compressibilities of OTE monolayers on untreated and plasma-treated mica and to estimate their surface densities and phase-states from the film compressibility. The compressibility moduli of OTE are (0.