(92b) Investigation of Interfacial Rheology & Foam Stability | AIChE

(92b) Investigation of Interfacial Rheology & Foam Stability


Grillet, A. - Presenter, Sandia National Laboratories
Koehler, T. P. - Presenter, Sandia National Laboratories
Yaklin, M. A. - Presenter, Sandia National Laboratories
Brooks, C. F. - Presenter, Sandia National Laboratories
Cote, R. O. - Presenter, Sandia National Laboratories
Castaneda, J. N. - Presenter, Sandia National Laboratories
Mondy, L. A. - Presenter, Sandia National Laboratories
Walker, L. M. - Presenter, Carnegie Mellon University
Reichert, M. D. - Presenter, Carnegie Mellon University

The rheology at gas-liquid interfaces strongly influences the stability and dynamics of foams and emulsions. Several experimental techniques are employed to characterize the rheology at liquid-gas interfaces with an emphasis on the non-Newtonian behavior of surfactant-laden interfaces. The focus is to relate the interfacial rheology to the foamability and foam stability of various aqueous systems. An interfacial stress rheometer (ISR) is used to measure the steady and dynamic rheology by applying an external magnetic field to actuate a magnetic needle suspended at the interface. Results are compared with those from a double wall ring attachment to a rotational rheometer (TA Instruments AR-G2). Micro-interfacial rheology (MIR) is also performed using optical tweezers to manipulate suspended microparticle probes at the interface to investigate the steady and dynamic rheology. Additionally, a surface dilatational rheometer (SDR) is used to periodically oscillate the volume of a pendant drop or buoyant bubble. Applying the Young-Laplace equation to the drop shape, a time-dependent surface tension can be calculated and used to determine the effective dilatational viscosity of an interface. Using the ISR, double wall ring, SDR, and MIR, a wide range of sensitivity in surface forces (fN to nN) can be explored as each experimental method has different sensitivities. Measurements will be compared to foam stability.


This work was supported by the Laboratory Directed Research and Development program at Sandia National Laboratories. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.