PEM Conductivity Sample Holder

The polymer electrolyte membrane (PEM) sample holder for ProboStat™ is a PEEK head to be mounted in the top of a standard ProboStat™ support tube. It has a flat top surface with 4 wire electrodes onto which the polymer film is pressed down with the spring load of the ProboStat™, for measuring the in-plane conductivity primarily of polymer electrolyte membrane films, but also other flexible and/or soft films.It can operate at temperatures and conditions where the PEEK and metal parts are stable, typically long term up to around 200°C, for shorter term e.g. 250°C. The PEEK head is replaceable.


Core material: PEEK

Electrodes: 4 electrodes in the shape of 4 integrated wires

Electrode wires: Au (default), Pt or Ag (all replaceable)

Contact from ProboStat™ base unit: Standard Pt or any other metal (e.g. Cu) wires

Mounting: Any length standard ProboStat™ 20 mm support tube

Sample fixation: Standard ProboStat™ spring load system

Temperature range: RT - 200~300°C

Heating: Heating mantle or tubular furnace (not included)

Atmosphere (ProboStat™): Oxidizing, inert, reducing, corrosive, wet or dry


  1. Perforated PEEK plate.

  2. PEEK head with 4 double-sided double electrode wire screw terminals.

  3. 4 (short) electrode wires with 0.5 mm diameter, typically of Pt, Au, or Cu. May be pre-mounted in the PEEK head. Extra electrode wires may be supplied separately if ordered.

  4. 4 (long) electrode connects, typically 0.5 mm diameter of Pt, Au, or Cu, lengths according to the length of the support tube. They have female mini-contacts in one end and are either insulated with plastic, or equipped with ceramic insulating tubes.

  5. Thermocouple assembly TCI-P consisting of type S or type K thermocouple wires in a two-bore alumina tube, with minicontacts, and colour-coded wire insulation


 Example measurements on Nafion®  N-115 membrane


  • First 4-electrode measurement – poorly contacting, polarizing electrodes 


Nyquist plot of Nafion N-115 and its equivalent circuit in ambient atmosphere

at room temperature measured by a 4-electrode configuration. The high

frequency arc is attributed to the bulk response, while artefacts of the

electrode responses are seen at low frequencies. The two numbers along

the graph show the AC frequency range.  

  • Temperature dependency


Log conductivity of Nafion N-115 as a function of inverse absolute temperature at constant partial pressure of water.






PEM conductivity sample holder brochure.

HumiStat brochure.

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