Non-Coalescence in Microgravity: Science and Technology

Non-coalescence of two bodies of the same liquid and the suppression of contact between liquid drops and solid surfaces (nonwetting) has been studied through a pair of parallel investigations being conducted at the Georgia Institute of Technology and the Microgravity Research and Support (MARS) Center in Naples, Italy. Both non- coalescence and nonwetting may achieved by either: i) exploiting the mechanism of thermocapillary convection to drive a lubricating film of surrounding gas (air) into the space between the two liquid free surfaces (non-coalescence) or between the drop free surface and the solid (nonwetting); or ii) using the otherwise forced motion of the solid (or one liquid) surface to generate the lubricating film. These, and other types of related phenomena are discussed in our recent review article (Neitzel GP, Dell'Aversana P. 2002. Noncoalescence and nonwetting behavior of liquids. Annual Review of Fluid Mechanics 34: 267-89). This project was a continuation of earlier research on this subject and includes the possible uses of non-coalescing/wetting systems in technological applications.