ESPCI web site
Antibubbles : optical interferometry, gas transfers and acoustic signature
An antibubble is a spherical thin film of gas, that encapsulates a droplet, within a liquid medium. The typical size of an antibubble is one centimeter while the thickness of the gas film is of micrometric order. Because of the higher hydrostatic pressure at the bottom, the gas film undergoes a gravitationally-driven drainage from the bottom to the top, that eventually leads to the film rupture and antibubble collapse. I will present recent experiments conducted on antibubbles made in surfactants-containing aqueous solutions. After introducing how one can produce these unusual objects by hand, I will show that the spherical geometry of the system allows for the determination of the thickness profile using only a monochromatic light source and a camera. This technique allowed to show that the thickness evolution in time is strongly affected by mass exchanges with the surrounding bulk ie by gas dissolution/desorption. An “antibubble column” was then designed to measure these fluxes and how the nature of surfactants used may affect them. Finally, I will describe an ongoing work on the acoustic response of an antibubble under exitation. Two resonances are measured with a 4 ms time resolution, I will discuss these results and our first steps to understand them.