Liquid Drops on Liquid Surfaces

Abstract

It is a common observation that drops of a liquid may exist for some time on the surface of the same liquid in bulk before coalescence occurs. Such drops are frequently observed during the process of refluxing an organic solvent, the splashing of raindrops in puddles, the drip of water from oars, or the splashing of sea water against a rocky shore. They are sufficiently interesting to have attracted the notice of several men whose observations have appeared from time to time in the scientific periodicals, e.g., Lord Rayleigh (8), Reynolds (9), Kaiser (5), Seth (10), and Mahajan (7).The drops are formed in two distinct ways. The falling drop may fail to penetrate the surface of the bulk liquid and may rest there, preserving its identity for a matter of many seconds, or it may fall with such force 1205

Persisting Water Droplets on Water Surfaces

“…Research into noncoalescence was taken a step further by another group 4 who focused on situations when droplet and bulk liquids were different. When different liquids with long polar molecules (molten fats, paraffin, drying oils) were used in droplets and in the bulk, floating droplets were readily produced.…”

“…On the basis of experimental results obtained when bulk and droplet fluids are different, Hazlehurst and Neville 4 proposed that delayed coalescence might originate from the fact that different liquids have different molecular structures, and thus some molecular rearrangement must take place for coalescence to occur. Depending on the extent of difference, noncoalescence duration could be shorter or longer.…”

Complex architectures formed by alginate drops floating on liquid surfaces

“…12 The formation of oating drops is, instead, more readily obtained when liquids with different molecular structure consisting of long polar molecules are used for the droplet and the bulk. 13 A state of permanent non-coalescence can be established by the creation of a lubricant uid lm between the involved interfaces. 14 In this paper, we investigate the oating of drops of sodium alginate, a polysaccharide derived from brown algae, on the surface of a water-based calcium chloride solution, and we follow the subsequent shape modication of the droplets during the alginate gelation due to the calcium ions, giving an insight into the related physics.…”

Effects of Electrostatic Forces on Drop Collision and Coalescence in Air

“…---) (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) Under this condition, the stability of the system varies as the inverse of the fourth power of the constant force, P , compared to only its 0 first power in (5-15), 'the difference being that the equation (5-15) did not include any change in the deformation as the surfaces move together.…”