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New sensitive micro-measurements of dynamic surface tension and diffusion coefficients: Validated and tested for the adsorption of 1-Octanol at a microscopic air-water interface and its dissolution into water.

Publication ,  Journal Article
Kinoshita, K; Parra, E; Needham, D
Published in: Journal of colloid and interface science
February 2017

Currently available dynamic surface tension (DST) measurement methods, such as Wilhelmy plate, droplet- or bubble-based methods, still have various experimental limitations such as the large size of the interface, convection in the solution, or a certain "dead time" at initial measurement. These limitations create inconsistencies for the kinetic analysis of surfactant adsorption/desorption, especially significant for ionic surfactants. Here, the "micropipette interfacial area-expansion method" was introduced and validated as a new DST measurement having a high enough sensitivity to detect diffusion controlled molecular adsorption at the air-water interfaces. To validate the new technique, the diffusion coefficient of 1-Octanol in water was investigated with existing models: the Ward Tordai model for the long time adsorption regime (1-100s), and the Langmuir and Frumkin adsorption isotherm models for surface excess concentration. We found that the measured diffusion coefficient of 1-Octanol, 7.2±0.8×10-6cm2/s, showed excellent agreement with the result from an alternative method, "single microdroplet catching method", to measure the diffusion coefficient from diffusion-controlled microdroplet dissolution, 7.3±0.1×10-6cm2/s. These new techniques for determining adsorption and diffusion coefficients can apply for a range of surface active molecules, especially the less-characterized ionic surfactants, and biological compounds such as lipids, peptides, and proteins.

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Published In

Journal of colloid and interface science

DOI

EISSN

1095-7103

ISSN

0021-9797

Publication Date

February 2017

Volume

488

Start / End Page

166 / 179

Related Subject Headings

  • Water
  • Thermodynamics
  • Temperature
  • Surface Tension
  • Solubility
  • Models, Chemical
  • Kinetics
  • Diffusion
  • Chemical Physics
  • Air
 

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Kinoshita, K., Parra, E., & Needham, D. (2017). New sensitive micro-measurements of dynamic surface tension and diffusion coefficients: Validated and tested for the adsorption of 1-Octanol at a microscopic air-water interface and its dissolution into water. Journal of Colloid and Interface Science, 488, 166–179. https://doi.org/10.1016/j.jcis.2016.10.052
Kinoshita, Koji, Elisa Parra, and David Needham. “New sensitive micro-measurements of dynamic surface tension and diffusion coefficients: Validated and tested for the adsorption of 1-Octanol at a microscopic air-water interface and its dissolution into water.Journal of Colloid and Interface Science 488 (February 2017): 166–79. https://doi.org/10.1016/j.jcis.2016.10.052.
Kinoshita, Koji, et al. “New sensitive micro-measurements of dynamic surface tension and diffusion coefficients: Validated and tested for the adsorption of 1-Octanol at a microscopic air-water interface and its dissolution into water.Journal of Colloid and Interface Science, vol. 488, Feb. 2017, pp. 166–79. Epmc, doi:10.1016/j.jcis.2016.10.052.

Published In

Journal of colloid and interface science

DOI

EISSN

1095-7103

ISSN

0021-9797

Publication Date

February 2017

Volume

488

Start / End Page

166 / 179

Related Subject Headings

  • Water
  • Thermodynamics
  • Temperature
  • Surface Tension
  • Solubility
  • Models, Chemical
  • Kinetics
  • Diffusion
  • Chemical Physics
  • Air