Droplet Spreading and Adhesion on Spherical Surfaces.

Adhesion of a liquid droplet to a solid surface is a result of solid surface interactions with surrounding fluids, affected by its wettability and morphology. Unfortunately, the direct measurements of adhesion forces are rarely reported in the scientific literature, especially for solids with curvatures. In this study, by using a high-sensitivity microelectronic mechanical balance which vertically deposits and then pulls liquid droplets, the spreading and adhesion forces for water and ethylene glycol droplets on spherical surfaces of polyethylene terephthalate (PET) with radii of curvature from 2 to 8 mm were recorded.

Droplet Characteristics at the Maximum Adhesion on Curved Surfaces.

For applications involving droplet detachment from solid surfaces, it is vital to study the droplet characteristics (e.g., contact angle and base width) when the droplet is experiencing the maximum force that detaches the droplet (maximum adhesion state).

Selective adsorption of a high-performance depressant onto dolomite causing effective flotation separation of magnesite from dolomite.

This research focused on the adsorption features and depression mechanism of 1-hydroxyethylene-1,1-diphosphonic acid (HEDP) used as a novel dolomite depressant on dolomite and magnesite surfaces, to extend the application of HEDP for the selective flotation of magnesite from dolomite. The depression impacts of HEDP on the flotation behaviors of the two minerals were investigated through micro-flotation tests. The flotation results indicated that, when sodium oleate (NaOl) was used as the collector, HEDP displayed an outstanding depression effect on the dolomite flotation, whereas it had only a slight influence on the magnesite flotation.

Contact Line and Adhesion Force of Droplets on Concentric Ring-Textured Hydrophobic Surfaces.

Advances made in fabrication of patterned surfaces with well-defined dimensions of topographic features and their lateral dissemination drive the progress in interpretation of liquid spreading, adhesion, and retreat on engineered solid surfaces. Despite extensive studies on liquid droplet spreading and adhesion on textured surfaces in recent years, conformation of the three-phase contact line and its effect on macroscopic contact angle and droplet adhesion remain the focus of intensive debate. Here, we investigate the effect of surface topography on the adhesion force of Cassie-Baxter-state droplets on concentric ring-textured hydrophobic surfaces having rings with lateral dimensions of 5, 10, and 45 μm and separated by 5, 6, and 7 μm trenches, respectively, with fixed depth of 15 μm.