Multiplex particle focusing via hydrodynamic force in viscoelastic fluids

Area of Science:

• Fluid Dynamics
• Microfluidics
• Particle Manipulation

Background:

• Viscoelastic fluids exhibit normal stress differences causing particle migration in microchannels.
• Dean drag force in spiral channels induces outward particle migration.
• Harnessing these forces is key for controlled particle focusing.

Purpose of the Study:

• To introduce and explain a multiplex particle focusing phenomenon.
• To investigate the interplay between viscoelastic and Dean drag forces.
• To propose a novel concept for microfluidic particle dynamics.

Main Methods:

• Utilized a microfluidic device with spiral channel geometry.
• Investigated hydrodynamic interactions between viscoelastic and Dean drag forces.
• Performed numerical analysis of viscoelastic fluid behavior in spiral channels.

Main Results:

• Demonstrated multiplex particle focusing based on fluid dynamics.
• Identified the 'Dean-coupled Elasto-inertial Focusing band (DEF)' phenomenon.
• Showcased the ability to focus different sized particles simultaneously.

Conclusions:

• The DEF phenomenon offers precise control over particle focusing in microfluidics.
• This finding opens new possibilities for high-throughput particle manipulation platforms.
• Provides physical insight into complex particle dynamics in microscale devices.