Paper Number
IR2                         My Program 

Session
Interfacial Rheology, Surfactants, Foams and Emulsions

Title
Self-Similar Growth of Nanoscopic Mesas in Stratifying Micellar Foam Films

Presentation Date and Time
October 20, 2025 (Monday) 10:10

Track / Room
Track 5 / O’Keeffe + Milagro

Authors (Click on name to view author profile)

1. Xu, Chenxian (University of Illinois Chicago, Department of Chemical Engineering)
2. Sharma, Vivek (University of Illinois Chicago)

Author and Affiliation Lines (in printed abstract book)
Chenxian Xu and Vivek Sharma
University of Illinois Chicago, Chicago, IL 60607

Speaker / Presenter 
Xu, Chenxian

Keywords
foams; microscopy; surfactants

Text of Abstract
Freestanding films of soft matter exhibit stratification due to confinement-induced structuring and layering of supramolecular structures like micelles. Stratification in micellar films proceeds by the growth of thinner domains at the expense of surrounding thicker film, and local volume conservation leads to the formation of nanoscopic ridges at the moving front. The ridge often undergoes an instability leading to nucleation of nanoscopic mesas, that grow and coalesce over time along the moving front. The shape and size of ridges and mesas in stratifying films are visualized and analyzed using interferometry, digital imaging, and optical microscopy (IDIOM) protocols, with unprecedented high spatial (thickness < 10 nm, lateral < 1 µm) and temporal resolution (< 1 ms). In this contribution, we analyze the self-similar of mesas in an effort to develop a comprehensive understanding of drainage by stratification in micellar foam films, including the role played by the contribution of supramolecular oscillatory structural forces to disjoining pressure.