i wanna know if there is any method to measure the thickness of diffuse double layer in lab ? I know there is a method using electrical conductivity but not sure how to do that .
Thanks
Do you want to measure it or calculate it? I've never heard of a way to measure it but there are standard ways to estimate the thickness if you know the ionic composition of the liquid.
Re. conductivity, do you mean measure? Again, it can be calculated if you know the conductivities of each species in solution.
Why do you need to know the thickness?
John Francis Miller Thanks for your answer. I wanna estimate the thickness of double layer. I can add salt for example to my solution and have control on the ionic composition of the liquid. How can i estimate that? first of all I wanna do that to bentonite alone. Then I would like to measure that to my treated bentonite with silica gel. Silica gel reduced the swelling of bentonite (on macro-level scale). I wanna explore the micro-level now and have an understanding of what silica gel does to bentonite? does the double layer thickness compress ?
Use the equation for kappa (k) here:
http://soft-matter.seas.harvard.edu/index.php/Debye_length
k is a bulk parameter and won't be affected by the presence of the particles of either type unless they are present at very high levels, the bulk electrolyte conc is low and there's a lot of repartitioning of electrolyte between the particle surface and the bulk. Basically, the presence of silica gel shouldn't influence anything.
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