# Influence of Substrate Conductivity on Circulation Reversal in Evaporating Drops

## Overview

• [1] Ristenpart, W., Kim, P., Domingues, C., Wan, J, & Stone, H. Physical Review Letters. 99, 234502-1 - 234502-4 (2007).
• Keywords: Evaporation, Marangoni Effect, Contact Angle, Thermal Conduction, Surface Tension

## Summary

In this paper, Ristenpart et. al. study the flow patterns inside liquid drops on flat surfaces. Evaporation from the drops' surfaces leads to a thermal gradient and, thus, a gradient in surface tension. Displaying the Marangoni effect, fluid flows from regions with low surface tension to regions with high surface tension. The authors ask, within the drop, what direction is this Marangoni flow? Using both theoretical and experimental approaches the authors determine conditions which result in two different flow patterns.

Critical K $k_{R}^{crit}=tan(\theta_{c})cot\left(\frac{\theta_c}{2}+\frac{\theta_c^2}{\pi}\right)$

Experiments