Microfluidic pump driven by anisotropic phoresis

TL;DR

This paper introduces a microfluidic pump driven by anisotropic phoresis, utilizing elongated tilted pillars in microchannels to induce fluid flow through thermophoretic effects, with potential applications in mixing, energy harvesting, and alternative phoretic mechanisms.

Contribution

It demonstrates how anisotropic thermophoresis of tilted pillars can be harnessed to create microfluidic pumps, expanding the understanding of phoretic-driven fluid manipulation.

Findings

Flow rate depends on channel geometry and pillar surface properties

Device can be used for fluid mixing and energy harvesting

Similar principles apply to diffusiophoresis and electrophoresis

Abstract

Fluid flow along microchannels can be induced by keeping opposite walls at different temperatures, and placing elongated tilted pillars inside the channel. The driving force for this fluid motion arises from the anisotropic thermophoretic effect of the elongated pillars that generates a force parallel to the walls, and perpendicular to the temperature gradient. The force is not determined by the thermophilic or thermophobic character of the obstacle surface, but by the geometry and the thermophoretic anisotropy of the obstacle. Via mesoscale hydrodynamic simulations, we investigate the pumping properties of the device as a function of the channel geometry, and pillar surface properties. Applications as fluidic mixers, and fluid alternators are also outlined, together with the potential use of all these devices to harvest waste heat energy. Furthermore, similar devices can be also built employing diffusiophoresis or electrophoresis.