9860

Debye Length in a Symmetric Electrolyte Solution

A charged surface immersed in a viscous electrolyte solution attracts ions of opposite charge. Yet the ions are also subject to thermal diffusion and hydrodynamic drag in the viscous medium. This creates a "cloud" of counter-ions above the surface known as the diffuse layer, electrical double layer, or Debye layer. The charge in the Debye layer is equal and opposite to the charge on the surface, effectively screening the charge on the surface. The thickness of the "cloud" is given by the Debye length , which is a function of ion concentration, ion valence, relative permittivity, and temperature of the fluid; you can vary these parameters using the controls. Interestingly, the Debye layer depends only on properties of the solution, not on the surface which it screens.
The Debye length is an important parameter in colloid science, particularly for electrophoresis (used for DNA sequencing and electrophoretic display technology) and electroosmotic pumping in microfluidics. The Debye length is also a measure of stability in a colloidal dispersion.

SNAPSHOTS

  • [Snapshot]
  • [Snapshot]
  • [Snapshot]

DETAILS

Reference
[1] W. B. Russel, D. A. Saville, and W. R. Schowalter, Colloidal Dispersions, Cambridge: Cambridge University Press, 1992.

    • Share:

Embed Interactive Demonstration New!

Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site. More details »

Files require Wolfram CDF Player or Mathematica.









 
RELATED RESOURCES
Mathematica »
The #1 tool for creating Demonstrations
and anything technical.
Wolfram|Alpha »
Explore anything with the first
computational knowledge engine.
MathWorld »
The web's most extensive
mathematics resource.
Course Assistant Apps »
An app for every course—
right in the palm of your hand.
Wolfram Blog »
Read our views on math,
science, and technology.
Computable Document Format »
The format that makes Demonstrations
(and any information) easy to share and
interact with.
STEM Initiative »
Programs & resources for
educators, schools & students.
Computerbasedmath.org »
Join the initiative for modernizing
math education.
Step-by-step Solutions »
Walk through homework problems one step at a time, with hints to help along the way.
Wolfram Problem Generator »
Unlimited random practice problems and answers with built-in Step-by-step solutions. Practice online or make a printable study sheet.
Wolfram Language »
Knowledge-based programming for everyone.
Powered by Wolfram Mathematica © 2014 Wolfram Demonstrations Project & Contributors  |  Terms of Use  |  Privacy Policy  |  RSS Give us your feedback
Note: To run this Demonstration you need Mathematica 7+ or the free Mathematica Player 7EX
Download or upgrade to Mathematica Player 7EX
I already have Mathematica Player or Mathematica 7+