Xth International Seminar on Inclusion Compounds (ISIC–10) September 19–23, 2005 Kazan, Russia The device for the measurement of conductivity of polymer microfibers T.E. Osmanov, I.V. Yaminsky Faculty of Physics, MSU, Leninskie gory, Moscow, Russia & Institute of Organoelement Compounds, RAS, Moscow, Russia.E-mail: [email protected] Summary Electric properties of polymer micro and nanofibers are practically not investigated. Such fibers are characterized by a high surface/volume ratio. They reveal good abilities to adsorb low-molecular substances. Composite fibers with metal inclusions are of special interest for the catalysis chemistry. Materials Device Polyacrylnitril (PAN) fiber with diameter from 20 up to 40 nanometers (Fig.1.) Fig.2. Picture of Polyacrylnytryl fibres made by electron microscope. Fig.4. Container with sample. Also on this figure you can observe termistor, special magnets for holding the sample and holes for sorbate. Fig.5. Measurement of electrical noise. Currentvoltage relation. We have constructed a precise device for the measurement of electric resistance of polymeric fibers. It is based on the FemtoScan scanning probe microscope and reveals several advantages: experiments can be performed in the environmental chamber using different adsorbates and at various temperatures. The temperature inside the chamber is controlled by thermistor, which acts also as a heater. The device allows to observe adsorption of different gases by the microfiber and to find its dependency upon temperature. Fig.3. Scheme of the device. 1 operational amplifier and container with sample, 2- digital-toanalog converter and analog-to-digital converter, 3 - DSPcard, 4 – server and client computers The dependence of the conductivity of PAN upon temperature and humidity of air is found; irreversible changes of a fiber conductivity are registered during the electrical current passage Temperature (time) The device can measure the resistance of fibers with accuracy 0.5%, i.e. 20-100 Om depending on fiber resistance. Fig.6. The change of electrical conductivity with temperature in open atmosphere. Temperature varies from 20 to 60 degrees centigrade. Resistance varies from 2750 to 3860 Om. Fig.7. Current-voltage relation of Polyacrylnitril fiber. Conclusion The application of the device for the studying gas-hydrates is proposed. It is possible to watch for adsorption by tracing changes of electrical resistance. The device can be used as a main part of the chemical sensor for the measurements of adsorption. The support of the Russian Foundation for Basic Research (project N 04-03-32472) and Russian Academy of Sciences (Program “Chemistry and physchemistry of supramolecular systems and atomic clusters”) is acknowledged.