Can we calculate the pore size and shape of a porous material or only it can be measured for single crystal using SAXS?
I we can calculate the pore size and shape then how it can be calculated?
You can calculate pore size with SAXS using Porod's law:
https://en.wikipedia.org/wiki/Porod%27s_law
There is extensive literature about it, for example:
Article Porosity by small-angle X-ray scattering (SAXS): comparison ...
https://www.sciencedirect.com/science/article/abs/pii/S0166516204000539
Hi Saud!
You cannot calculate the pore size by SAXS, instead of that you can calculate it by NMR or BET techniques.
Best regards,
Juliane
You can always apply the SAXS technique for obtaining pore size distributions if you have a two-phase system with quite a nice electron density differences. SAXS procedure determines the volume-weighted particle (or pore) size distribution Dv(R) from the scattering curve of an ensemble of spherical particles (or pores) having a homogeneous inner electron density distribution, and not showing interparticle interaction effects. The Dv(R) function refers to the volume-weighted particle size distribution ('volume distribution'). It may be seen as a histogram of the radii R of the particles that are present in the sample. The height of the Dv(R) function is proportional to the volume (not to the number) of particles that can be found within a given size interval when Dv(R) is normalized. then Dv(R)dR is the probability (by particle volume) of particles having a radius within an (infinitely small) interval dR. For spherical particles, the volume-weighted size distribution Dv(R) is related to the number-weighted size distribution Dn(R) by: Dv(R) ~ 4π/3 R3 Dn(R) The number-average of the particle size is always smaller than its volume-averaged value. The difference increases with increasing size polydispersity. Note that with electron microscopic techniques normally number distributions are determined.
I have found an article of the University of Kent at Canterbury UK by JC Dole, JB Webber and JH Strange that was describing N2 sorption results, NMR results and SANS measurements.
In that publication it was indicated that it was difficult to obtain clearly the contribution of micropores. About SAXS, I am still looking for information. Let me know if you find an interesting paper.
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