Quantitative imaging of the complexity in liquid bubbles’ evolution reveals the dynamics of film retraction

Abstract

The dynamics and stability of thin liquid films have fascinated scientists over many decades. Thin film flows are central to numerous areas of engineering, geophysics, and biophysics and occur over a wide range of lengths, velocities, and liquid property scales. In spite of many significant developments in this area, we still lack appropriate quantitative experimental tools with the spatial and temporal resolution necessary for a comprehensive study of film evolution. We propose tackling this problem with a holographic technique that combines quantitative phase imaging with a custom setup designed to form and manipulate bubbles. The results, gathered on a model aqueous polymeric solution, provide unparalleled insight into bubble dynamics through the combination of a full-field thickness estimation, three-dimensional imaging, and a fast acquisition time. The unprecedented level of detail offered by the proposed methodology will promote a deeper understanding of the underlying physics of thin film dynamics.

3D monitoring of the surface slippage effect on micro-particle sedimentation by digital holographic microscopy

“…In conclusion, we measured the proximity effect of the wall on the sedimentation of colloidal microspheres near the surfaces with different slip lengths by the use of digital holographic microscopy (DHM). DHM provides quantitative phase-contrast and 3D imaging in arbitrary time scales, which makes it a suitable method to investigate various phenomena, including the dynamic behavior of colloids in 3D 22 – 24 , 60 – 62 . We have observed that for lower slip length values, the proximity effect is more pronounced, while the falling velocity variation of the particles increases by the slip length of the wall.…”

Structural Coloration by Internal Reflection and Interference in Hydrogel Microbubbles and Their Precursors

“…[ 19–23 ] To evaluate bubbles’ evolution, radius and shell thickness are the commonly used structural parameters, while bubbles’ shell thickness can hardly be accurately measured by normal optical microscope. [ 23,24 ] At present, different techniques have been proposed and implemented to monitor the film thickness's alteration. [ 24,25 ] For instance, interferometry is engaged to analyze the fringes formed by the interference of reflected light from the thin film's two interfaces.…”

“…[ 23,24 ] At present, different techniques have been proposed and implemented to monitor the film thickness's alteration. [ 24,25 ] For instance, interferometry is engaged to analyze the fringes formed by the interference of reflected light from the thin film's two interfaces. Though the technique can measure the film thickness over a large area in a real‐time manner, it can hardly provide more geometrical information about an evolving microbubble as a whole.…”

“…Though the technique can measure the film thickness over a large area in a real‐time manner, it can hardly provide more geometrical information about an evolving microbubble as a whole. [ 24 ]…”

Fast and Accurate Thickness Mapping of Thin Liquid Films

“…Herein, we tackle this problem using a holographic technique that combines quantitative phase imaging with a custom setup designed to form and manipulate bubbles [5]. digital holography (DH) is often used in sensors and microscopes to assess small variations of concentration [6], cell mass profiling [7] or thickness in transparent samples below the diffraction limit [8,9].…”