Abstract

Dipolar Thermocapillary Motor and Swimmer

Moran Bercovici, Assistant Professor, Technion – Israel Institute of Technology

The ability to manipulate fluids at the microscale is a key element of any lab-on-a-chip platform, enabling core functionalities such as liquid mixing, splitting and transport of molecules and particles. Lab-on-a-chip devices are commonly divided in two main families: continuous phase devices, and discrete phase (droplets) devices. While a large number of mechanisms are available for precise control of droplets on a large scale, microscale control of continuous phases remains a substantial challenge. In this talk I will present our ongoing work leveraging thermocapillary flows to induce and control flows in microfluidic channels.  I will begin by providing theoretical background on thermocapillary dipoles induced in a Hele-Shaw cell with a small circular opening, and show that such a configuration can act as a thermocapillary motor capable of driving liquids through micro-channels and in Hele-Shaw type devices. I will then demonstrate that thermocapillary dipoles can be superposed in order to create various two-dimensional flow patterns, allowing for transport of liquids which are not confined to a one-dimensional micro-channel. Finally, I will show that the same principles can be applied to create a new type of surface swimmer whose motion is activated by illumination.