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Title: Investigation of interfacial rheology & foam stability.

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 hasmore » different sensitivities. Measurements will be compared to foam stability.« less
Authors:
; ; ;  [1] ; ; ; ; ;
  1. (Carnegie Mellon University, Pittsburg, PA)
Publication Date:
OSTI Identifier:
1012444
Report Number(s):
SAND2010-2896C
TRN: US201110%%21
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the Annual Meeting of the American Institute of Chemical Engineers held November 7-12, 2010 in Salt Lake City, UT.
Research Org:
Sandia National Laboratories
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; FOAMS; INTERFACES; STABILITY; RHEOLOGY; SURFACE TENSION; VISCOSITY; MEASURING METHODS; SURFACE FORCES