PPY THIN-LAYERS GROWN ONTO COPPER SALT REPLICA FOR SENSOR ARRAY FABRICATION

Investigations on polypyrrole, a pi-electron conjugated conducting polymer, aimed at the realization of amperometric biosensors are presented. The intent is to realize multi-electrode devices capable of transducing chemical changes into electrical signals. Thin patterned films of polypyrrole, which electrically interconnect Au microelectrodes, were grown from vapour phase by using a saline compound, CuCl2 + 2H2O, as oxidant. The salt has been obtained by a selective oxy-chloridization procedure of Cu thin layers on Au electrodized substrates. This technique has been used since it permits easier control, more than with electrochemical growth, of the polymer geometry which depends only on the salt geometry, hence on the Cu coating. Preliminary results obtained by means of cyclic voltammetry at a scan rate of 100 mV s-1, performed at different pHs (2, 7.8, 9, 12) on chemically grown PPy from CuCl2 + 2H2O salt, demonstrated that polymer conductivity increases in acid solution as the pH decreases.