Duration: 36 months
Aqueous foams are encountered in many commercial products and are widely studied. Non-aqueous foams, though crucial in various industries have been less explored compared to aqueous foams. In the food industry, vegetable oil foams are of particular interest to the consumer due to their low-calorie count and desirable mouth-feel. In pharmaceutical industry, foams based on ethanol for hand sanitizing is attracting interest due their unique texture. These non-aqueous foams are also pivotal in space exploration for processes like life support systems and food production, face challenges like rapid drainage due to gravity. In lubricating oils added to engines, problems such as cavitation, oil degradation occur when air becomes entrapped. In the food industry, the foam produced during frying oil is also undesirable. In these scenarios, it is essential to understand what causes a stable oil foam.
Liquid foams are dispersions of gas bubbles in a liquid phase. Because of the large density difference between air and the liquid, this liquid drains rapidly due to gravity and dry foams are obtained. Coarsening and coalescence are coupled with gravity drainage and are faster when the foam liquid fraction is lower. These foam destabilization mechanisms have been widely studied for aqueous foams on Earth and under microgravity conditions. Unlike aqueous foams, understanding drainage, coarsening, and coalescence in non-aqueous foams remains limited, hindering predictive behavior and stability assessment. It is serious drawback for developing further their applications. Furthermore, low gravity conditions are expected to change the mechanisms, as observed in the recent experiments onboard the ISS. This postdoctoral project aims to investigate different non-aqueous foam systems in microgravity, focusing on foamability, drainage suppression, and coarsening stabilization mechanisms. This research is essential for enhancing applications reliant on non-aqueous foams.
