Soap Bubbles Formation and Stability

Perhaps the phenomenon of bubble formation is the most common observation mankind experiences since childhood. Bubbles are also commonly observed in many different instances  

One also knows that soap bubbles are extremely thin (1000 times thinner than the diameter of a hair ) and unstable (Birdi, 1997 Boys, 1959 Li et al., 2014 Lovett, 1994 Scheludko, 1966  

Taylor, 2011). In spite of the latter, under special conditions, one can keep soap bubbles for long lengths of time, which thus allows one to study its physical properties (such as thickness, composition, conductivity, spectral reflection, etc.). The thickness of a bubble is in most cases over hundreds of micrometers in the initial state. The thin liquid film (TLF) consists of bilayer of detergent that contains the solution. The film thickness decreases with time due to following reasons  

Therefore, the stability and lifetime of such thin films will be dependent on these different characteristics. This is found from the fact as an air bubble is blown under the surface of a soap or detergent solution, air bubble will rise up to the surface. It may remain at the surface, if the speed is slow, or it may escape into the air as a soap bubble. Experiments show that a soap bubble consists of a very TEE with an iridescent surface. But as the fluid drains away and the thickness decreases, the latter approaches to the equivalent of barely two surfactant molecules plus a few molecules of water. It is worth noting that the limiting thickness is on the order of two or more surfactant molecules. This means that one can see with the naked eye molecular size structures of TLFs. As the air bubble enters the surface region, the soap molecules along with water molecules are pushed up and as the bubble is detached, it leaves as a TLF with following characteristics (as found from various measurements)  

The thickness of the initial soap bubble is some micrometers. 

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