RT Journal Article
T1 Interfacial mechanisms for stability of surfactant-laden films
A1 Bhamla, M. Saad
A1 Álvarez Valenzuela, Marco Antonio
A1 Tajuelo, Javier
A1 Fuller, Gerald G.
AB Thin liquid films are central to everyday life. They are ubiquitous in modern technology (pharmaceuticals, coatings), consumer products (foams, emulsions) and also serve vital biological functions (tear film of the eye, pulmonary surfactants in the lung). A common feature in all these examples is the presence of surface-active molecules at the air-liquid interface. Though they form only molecular-thin layers, these surfactants produce complex surface stresses on the free surface, which have important consequences for the dynamics and stability of the underlying thin liquid film. Here we conduct simple thinning experiments to explore the fundamental mechanisms that allow the surfactant molecules to slow the gravity-driven drainage of the underlying film. We present a simple model that works for both soluble and insoluble surfactant systems in the limit of negligible adsorption-desorption dynamics. We show that surfactants with finite surface rheology influence bulk flow through viscoelastic interfacial stresses, while surfactants with inviscid surfaces achieve stability through opposing surface-tension induced Marangoni flows.
PB PLOS
SN 1932-6203
YR 2017
FD 2017-05-17
LK https://hdl.handle.net/10016/38564
UL https://hdl.handle.net/10016/38564
LA eng
NO The authors received no specific funding for this work. However, J. T. acknowledges a personal grant from UNED's Researchers Formation Program and partial support from MINECO (Grant FIS2013-47350-C5-5-R).
DS e-Archivo
RD 18 jul. 2024