(421b) Mechanistic Insights into Lubricant Foaming and Foam Control Using Single Bubble Techniques

Lubricant foams are detrimental to lubricated machinery, causing well documented operational and maintenance challenges including increased wear of machine parts and reduced lubricant life. In this talk, we highlight advances in understanding lubricant foams using single bubble techniques (Adv. Colloids Interface Sci. 2020:102295), a class of foam characterization experiments where repeated coalescence experiments utilizing single bubbles are performed to evaluate foam stability and foam stabilization mechanisms. The utility of single bubble experiments for lubricant formulators will be highlighted through two separate examples. First, we use single bubble experiments to reveal a new mechanism of foam stabilization in blended lubricant base oils – evaporation induced Marangoni flows (PNAS 115(31) 7919-7924). Second, we show how this new foam stabilization mechanism can be utilized to develop lubricants and metal working fluids that are intrinsically foam resistant.