Thermocapillarity in Microfluidics-A Review

Area of Science:

• Physics and Chemistry
• Microfluidics and Nanotechnology

Background:

• Thermocapillarity, the change in surface tension with temperature, drives Marangoni flow.
• This flow is significant in microfluidic systems where surface tension effects dominate.
• The Benard-Marangoni effect describes thermocapillary-driven mass transfer.

Purpose of the Study:

• To review past and recent studies on thermocapillarity in microfluidics.
• To discuss the role of thermocapillarity in bubble and drop actuation.
• To present various thermocapillary-based microfluidic devices and their characteristics.

Main Methods:

• Review of existing literature on thermocapillarity and microfluidics.
• Analysis of thermocapillary effects on flow patterns in liquid films and drops.
• Examination of the relationship between evaporation and thermocapillary instability.

Main Results:

• Thermocapillarity induces Marangoni flow, crucial for actuating microfluidic drops and bubbles.
• This flow influences drop/bubble motion via interfacial drag, mass conservation, gravity, and buoyancy.
• Microfluidic applications leverage thermocapillarity for actuation, sensing, sorting, mixing, and assays.

Conclusions:

• Thermocapillarity is a key mechanism for microfluidic manipulation and device operation.
• Diverse microfluidic devices utilize thermocapillary effects for various applications.
• Further research and development in thermocapillary microfluidics offer significant potential.