Thermocapillary Flow on Superhydrophobic Surfaces

TL;DR

This paper explores thermocapillary flow over superhydrophobic surfaces, deriving analytical models and demonstrating potential for microfluidic pumping driven by temperature-induced surface tension gradients.

Contribution

It provides the first analytical expression for thermocapillary flow velocity on superhydrophobic surfaces and compares it with numerical solutions, highlighting its application in microfluidic pumping.

Findings

Large flow velocities can be induced by moderate temperature gradients.

Analytical and numerical results show good agreement.

Potential for microfluidic pumping applications.

Abstract

A liquid in Cassie-Baxter state above a structured superhydrophobic surface is ideally suited for surface driven transport due to its large free surface fraction in close contact to a solid. We investigate thermal Marangoni flow over a superhydrophobic array of fins oriented parallel or perpendicular to an applied temperature gradient. In the Stokes limit we derive an analytical expression for the bulk flow velocity above the surface and compare it with numerical solutions of the Navier-Stokes equation. Even for moderate temperature gradients comparatively large flow velocities are induced, suggesting to utilize this principle for microfluidic pumping.