Rheofluidics: frequency-dependent rheology of single drops

TL;DR

Rheofluidics is a novel microfluidic method that measures the frequency-dependent rheological properties of individual micron-scale objects, revealing new insights into their viscoelastic behavior and surface tension at different frequencies.

Contribution

This work introduces Rheofluidics, a microfluidic technique for single-particle rheology, enabling measurements unattainable with traditional bulk methods.

Findings

Frequency-dependent surface tension of surfactants

High-frequency viscoelasticity of microgels

Frequency-dependent bending modulus of vesicles

Abstract

We present Rheofluidics, a microfluidic technique that measures the frequency-dependent rheology of individual micron-scale objects. We apply oscillatory hydrodynamic stresses by flowing them through channels with modulated constrictions, and measure their deformation. Unlike bulk rheology, which measures collective properties, Rheofluidics provides heretofore unattainable measurements of individual particles. We apply Rheofluidics to discover frequency-dependent surface tension of surfactants, very high-frequency viscoelasticity of microgels and unexpected frequency-dependent bending modulus of vesicles.