Membranes containing new large size calixarenes on semiconductor substrates for chemical microsensors

New large size calixarenes have been synthesized and tested as ionophores. The applications of these new even-membered macrocycles in the field of chemical sensors have been studied. Thin p-tert-butyl calix[10 and 12]arenes film were deposited using the technique of thermal evaporation under vacuum on ISFET (Ion Sensitive Field Effect Transistor) and EIS structures (Electrolyte Insulator Semiconductor) surfaces. It was verified that by liquid chromatography the calixarene layers, after the sublimation process did not undergo any degradation. Electrochemical measurements with EIS structures and ISFETs were made to test the sensing properties of these calixarene films towards heavy metals. These large size calixarenes have shown a Nernstian sensitivity and a good selectivity towards iron(III) ions for the p-tert-butyl calix[12]arene and silver(I) ions for the p-tert-butyl calix[10]arene. A long lifetime was obtained for these sensors when tested over a large pH range. These materials present a real and great promise for further developments.