If a doped polymer has conductivity of 0.1 S/cm obtained by four point measurements (electrically), will the conductivity of this polymer obtained by in-situ electrochemical measurements be close by?
Yes, as there is only one definition of electrical conductivity, the value should be the same. If it is not, it can be due to heterogeneities in the system, i.e. a local conductivity can take a different value than the global (bulk) one, and also because one value was obtained with dc current and the other one was obtained with ac current. And the conductivity is known to be able to vary by several orders of magnitude depending on frequency.
Alain
The conductivity can vary from one technique to another. The four probe can give accurate value for thin and not very resistive films to avoid measuring the contact resistance. Electrical Conductivity fiom electrochemcal measuremements is measured indirectly and should take into account the various interfaces.
Not necessary. Conductivity value depends up on the sampling and also technique which we are uing. Four probe method is measurement under DC condtions. electrochemical method is measurement under AC conditions.
This is exactly what I said, it may depend on the method, but it should not. If the method changes the result, it means that you don't mesure the same thing, and this may bring you important knowledge about the material. But as far as you measure the same thing (dc on one hand or ac on the other hand at the same frequency, and with the same sampling), your resut should be the same.
Alain
Thank you all for your valuable comments!
According to my understanding, in electrochemical process, there are several sources of current which we used for conductance measurements (by dividing with potential applied) e.g. current by electronic motion through polymer martix, faradic current, capacitive current. Therefore, the conductance value obtained from four probe measurements should not be same.
If anyone can suggest some good reference related to this??
Thanks a lot!
Wish you all a very happy new year
Regards,
Rekha
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