Abstract
The role of absolute viscosities on the dynamics of droplet spreading on solids and droplet-droplet coalescence in liquid-liquid systems is experimentally characterized for a broad range of fluid parameters. We show in particular the existence of a viscous function based on both inner and outer fluid viscosities that allows for the determination of the critical wetting velocity and the evolution of contact diameters during immersed spreading and coalescence of droplets. This work quantifies the cooperative effects of fluid viscosities on droplet dynamics as well as their overall reduced influence from initial wetting to spreading and coalescence, which provides insights into the role of wetting contact lines on spontaneous capillary phenomena.
- Received 6 August 2017
DOI:https://doi.org/10.1103/PhysRevFluids.2.111601
©2017 American Physical Society