By Josh Perry, Editor
Researchers at the Universities of Edinburgh and Warwick (U.K.) used supercomputers to run molecular simulations and analyze the interactions between thermal-capillary waves, the ripples on the surface of droplets that are invisible to the naked eye, and discover the mechanisms behind droplets combining on a surface.
Researchers used supercomputer simulations to see how water droplets combined. (Wikimedia Commons)
According to a report from Edinburgh, the researchers saw that the ripples make first contact between droplets and once they come into contact the surfaces combine “like the zip on a jacket.”
Among the many applications for this nanoscale understanding of droplets are next-generation liquid cooling systems for high-powered electronics and improved 3-D printing techniques.
The research was recently published in Physical Review Letters. The abstract read:
“The classical notion of the coalescence of two droplets of the same radius R is that surface tension drives an initially singular flow.
“In this Letter we show, using molecular dynamics simulations of coalescing water nanodroplets, that after single or multiple bridges form due to the presence of thermal capillary waves, the bridge growth commences in a thermal regime.
“Here, the bridges expand linearly in time much faster than the viscous-capillary speed due to collective molecular jumps near the bridge fronts. Transition to the classical hydrodynamic regime only occurs once the bridge radius exceeds a thermal length scale lT∼√R.”