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

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.