Dear all, similar questions have been already discussed within RG. AFM and STM may be used. Other information in the following links. My Regards

https://www.researchgate.net/post/How_can_we_test_the_conductivity_of_a_polymer

https://www.researchgate.net/post/Is_it_possible_to_measure_the_conductivity_of_polymer_fibres

https://www.researchgate.net/post/How_do_I_measure_conductivity_on_conductive_polymer_films_50-100_m_without_a_four-point_probe

https://www.dti.dk/electrical-conductivity-in-materials/measuring-techniques/27779,2

https://www.nature.com/articles/srep01991

https://www.ossila.com/products/four-point-probe-system?variant=31916570945

Thanks a lot That was really helpful.

If we are talking about macro measurements: Normally conductivity of polymers is not measured with a 4 points probe but rather between two circular shape plates with the sample to measure in between the two plates.

Conductivity of polymers is relatively low and a four probe measurement wouldn't provide accurate results...

Md,

I do not have an answer to where you can buy a 4-point probe, but making a good probe is not difficult if you have a little machining experience. Let me share what I learned when I visited my friend Yosef Elabd's lab at Drexel University before he moved to Texas. This is a 4-wire method designed to measure conductivity in the plane or on the surface rather than normal to the plane of a polymer film. The normal conductivity is most easily measured as described above by Enrico Corniani. The attached paper (ACS Appl Mater Interfaces VOL. 2 • NO. 3 • 649–653 • 2010) illustrates using both types of techniques in films of SWCNT/latexes. The 4-wire probe has 4 parallel Pt wires about an inch long. They are held in a plastic harness, and alligator clips are attached in making a connection to a galvanostat or other electrochemistry or computer apparatus to measure and apply voltage and current. Ideally applying a current through the outer two and measuring a voltage across the inner two gives a DC measurement approach. In practice we do a frequency series and a Nyquist type plot and estimate the resistance obtained in the limit of zero frequency.through. Conductivity is calculated by d/[AR], where d is the ,separation of inner wires in cm, A is film cross-sectional area in cm^2 (thickness x width), and R is the zero-frequency resistance mentioned above. You can infer in-plane conductivity and surface conductivity, by taking opposite limits of results as a function of film thickness. My former assistant, Rene Crombez, made a very nice "cell" and I would be happy to share photos with you once I am allowed back into my office at university. Since we work in the same state (MI), we both miust await the governor's clearance to return to our labs. Feel free to contact me directly by email or phone - my coordinates are easy to find. John

We could measure four (point[1]) probe conductivity, only, for a (medium to) highly conductive polymers.

However, we might extent a four (non point) probe (practical) conductivity measurements using metallic strips (Au, Ag, In, Carbon paper, etc.) instead of the (traditional) point contacts[2]. Also, we can overcome special complexities by applying four probe Li-conductivity measurements of highly conductive polymeric Li-membranes electrolytes in new SS-LiBs, using four Li-metal strips.

1. Four-Point Probe, Low Price Resistance Measuring System https://cdn.shopify.com/s/files/1/0823/0287/files/four-point-probe-close-up.jpg?13569251807686032379 https://www.ossila.com/products/four-point-probe-system?wvideo=f9kad60pcv

2. see Figure12.11 (and Figure12.12, page_381), in: Electrical Conductivity in Polymer-Based Composites: Experiments, Modelling ... https://books.google.gr/books?hl=el&lr=&id=wuR8DwAAQBAJ&oi=fnd&pg=PA365&dq=Methods+of+Measuring+Electrical+Properties+of+Material&ots=WhF0wGe3rh&sig=Db2Xp_yYCe5v2sspGW3edMrjrUE&redir_esc=y#v=onepage&q=Methods%20of%20Measuring%20Electrical%20Properties%20of%20Material&f=false

3. in order to avoid contact 'Resistance(s)' and most of the (highly non-Ohmic, potentially corrosive) interfaces' complications.

I used to use a linear 4-point probe. It was homemade and very simple. A PTFE disc about 2cm diameter with four contacts about 2mm apart.

https://onlinelibrary.wiley.com/doi/full/10.1002/app.48820?casa_token=5j0aWL4u6DkAAAAA%3AqVHuxX27uMmbGGK3dsmbKy4YF2dwAqfDm2SX7vnhHzP_c7UdNj9Rv5PPavVUDbStx3Hk85s_pyGwAPG_

Article 3D Printing of Electrically Conductive Hydrogels for Tissue ...

with 3 probe cell you can measure the volume and surface electrical conductivity of the polymer with DC urrent. the reference is

1- ASTM, Annual Book of standards, D.C. Resistance or conductivity of insulating materials D527, part 39. Philadelphia: American society of testing and materials, 1981. while with four probe is by used AC current and it was to measure the angle of face retarding

Dear Prof Abdelkader BOUAZIZ, many thanks about these links. That would help me a lot.

There exist Metriso apparatus from Romex specially developed for that , it measures surface volume under maxi 100V DC

Cheers

Md Saleh Akram Bhuiyan

Another approach would be to use concentric probe method to determine volumetric resistivity (Ohm/Square) in accordance with ASTM D257. A reciprocal of that would be conductivity (Siemens/cm or S/m).

Here's where you can procure it.

http://www.trekinc.com/Monroe/272a.html

https://www.astm.org/Standards/D257.htm

You might use an electrometer with sensitivities above 10^16 OHMS (or so) to get a percolation plot. or a solid state Potenciostat which also allows to measure high resistivities. That's not easy to find. I would agree with the concentric probe that someone else mentioned previously... Good luck!.