Electrical measurements on the system tetrahydrofuran–polytetrahydrofuran–iodine

The ‘gel electrolyte’ composed of polytetrahydrofuran (POLYTHF), tetrahydrofuran (THF) and iodine has been prepared by heating near to the ceiling temperature the iodine solution in THF or by electrolyzing the iodine–THF solutions at room temperature. In both cases, the freshly prepared systems iodine–THF and POLYTHF–THF–iodine have been characterized by several electrical measurements in AC and DC current. The conductivity of these systems arises from the charge-transfer interaction between I2 and THF, which leads to the formation of iodide ions and positively charged oxonium ions of THF. The oxonium ions could involve also the presence of complexed iodine cations, which could be responsible for THF polymerization. The electrolyzed system POLYTHF–THF–iodine acts as a concentration pile whose tension arises from the concentration gradients present in the electrolytic cell.