Surfactant-laden bubble dynamics under porous polymer films.

Area of Science:

• Fluid dynamics
• Materials science
• Surface chemistry

Background:

• Air bubble dynamics under solid substrates are crucial for applications like mineral processing and gas capture.
• Ultra-thin porous films offer unique interfaces for studying these phenomena.
• Understanding bubble-film interactions is key to optimizing processes involving gas-liquid-solid interfaces.

Purpose of the Study:

• To investigate the spreading and permeation of air bubbles on an ultra-thin, porous ultra-high-molecular-weight polyethylene (UHMWPE) film.
• To analyze the influence of surface-active species (surfactants and proteins) on bubble dynamics and permeation.
• To evaluate the potential of UHMWPE films for applications requiring controlled gas-liquid-solid interactions.

Main Methods:

• High-speed videography was employed to record bubble interactions with the UHMWPE film.
• Experiments were conducted with and without the presence of surfactants and proteins.
• Bubble spreading, contact, and permeation through the porous film were analyzed.

Main Results:

• Air bubbles spread on the film after liquid dewetting and shrink due to gas permeation.
• Surface-active molecules (surfactants, proteins) significantly altered bubble-film interactions.
• The presence of these molecules reduced bubble permeation flux due to decreased capillary driving force and film permeability.

Conclusions:

• The ultra-thin UHMWPE film exhibits high permeation flux, making it suitable for applications like froth flotation and methane capture.
• Surface-active species modulate bubble permeation, impacting process efficiency.
• This research elucidates the complex interplay between bubble dynamics, porous films, and interfacial chemistry.