A simple method of measuring profiles of thin liquid films for microfluidics experiments by means of interference reflection microscopy

TL;DR

This paper introduces a straightforward optical method using interference reflection microscopy to visualize and reconstruct the profiles of thin liquid films in microfluidic experiments, aiding in the analysis of droplet and bubble flows.

Contribution

The paper presents a novel, simple approach combining interference reflection microscopy with numerical analysis for measuring thin liquid film profiles in microfluidics.

Findings

Effective visualization of thin film topography

Numerical reconstruction of film profiles from interference patterns

Potential applications in microfluidic droplet and bubble studies

Abstract

A simple method was developed to observe the interference patterns of the light reflected by the interfaces of thin liquid films. Employing a fluorescent microscope with epi-illumination, we collected the 2D patterns of interference fringes containing information of the liquid film topography at microscale. To demonstrate the utility of the proposed visualization method we developed a framework for reconstructing the profiles of liquid films by analysing the reflected interferograms numerically. Both the visualization and reconstruction methods should be useful for variety of microfluidic applications involving the flows with droplets and bubbles in which the knowledge of the topography of the interfacial liquid film is critical.