Mar 22 2019
In a discovery that could have wide-ranging implications, researchers have shown the exact molecular mechanisms that bring about the union of liquid droplets.
The study suggests that an understanding of merging of droplets can potentially help in making 3D-printing technologies more accurate and might enhance the prediction of thunderstorms and other weather effects.
Simulated Interactions
A research team from the Universities of Edinburgh and Warwick performed molecular simulations on a supercomputer to examine the interactions between small ripples created on the surface of droplets.
These ripples—called thermal-capillary waves—are very small to be noticed either by the naked eye or by using the most modern experimental methods.
Scientists discovered that these small waves pass over the gap between adjacent droplets and cause collisions.
The researchers stated that once the droplets collide, liquid molecules bring the two surfaces together similar to the zip on a jacket, leading to the complete union of the droplets.
Liquid Behavior
The research team expressed that the study of the dynamics of merging droplets could enhance insights into the conditions causing raindrops to form in evolving storm clouds.
ARCHER UK National Supercomputing Service—operated by EPCC, the university’s high-performance computing facility—was used by the researchers to carry out their simulations, which involved using several processors to model interactions between about five million atoms.
This study, reported in Physical Review Letters, received financial support from the Engineering and Physical Sciences Research Council.
We now have a good understanding of how droplets combine at a molecular level. These insights, combined with existing knowledge, may enable us to better understand rain drop growth and development in thunderstorms, or improve the quality of printing technologies. The research could also aid in the design of next-generation liquid-cooling systems for new high-powered electronics.
Sreehari Perumanath, School of Engineering, University of Edinburgh.
The theoretical framework developed for the waves on nanoscale droplets enabled us to understand Edinburgh’s remarkable molecular simulation data. Critically, the new theory allows us to predict the behaviour of larger engineering-scale droplets, which are too big for even ARCHER to capture, and enable new experimental discoveries.
Dr James Sprittles, Mathematics Institute, University of Warwick.