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Title: High-precision instrument for measuring the surface tension, viscosity and surface viscoelasticity of liquids using ripplon surface laser-light scattering with tunable wavelength selection

Journal Article · · Review of Scientific Instruments
DOI:https://doi.org/10.1063/1.4871992· OSTI ID:22254911
;  [1];  [2]
  1. School of Integrated Design Engineering, Keio University, Yokohama 223-8522 (Japan)
  2. Department of System Design Engineering, Keio University, Yokohama 223-8522 (Japan)

Here we describe our new high-precision instrument that simultaneously measures the surface tension, viscosity, and surface viscoelasticity of liquids. The instrument works on the ripplon surface-laser light scattering principle and operates with an automatically tunable selection of ripplon wavelength from 4 to 1500 μm, which corresponds to the frequency range of observing surface phenomena from approximately 400 Hz to 3 MHz in the case of water. The heterodyne technique instrument uses a reference laser beam which intersects at an arbitrarily adjustable angle with a vertically directed probing beam. For the determination of the wavelength of selected ripplons we substituted with the interference fringe spacing, measured using a high-resolution beam profiler. To extract reliable surface tension and viscosity data from the experimentally obtained spectrum shape for a selected wavelength of ripplon, we developed an algorithm to calculate the exact solution of the dispersion equation. The uncertainties of surface tension and viscosity measurement were confirmed through the measurement of seven pure Newtonian liquids at 25 °C measured with the selected wavelength of ripplon from 40 μm to 467 μm. To verify the genuine capability of the tunable wavelength selection of ripplon, we measured the surface elasticity of soluble surface molecular layers spread on pentanoic acid solutions.

OSTI ID:
22254911
Journal Information:
Review of Scientific Instruments, Vol. 85, Issue 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
Country of Publication:
United States
Language:
English