Electrodeposited Copolymer Films with Tunable Conductivity

Conducting copolymer films were prepared from pyrrole (Py) and 1,12-di-(1-pyrrolyl) dodecane (DiPy) in an attempt to prepare conducting films that can be used as sensitive material of chemiresistor gas sensors. Copolymer thin films were obtained by electrochemical oxidation in a lithium perchlorate/acetonitrile electrolyte with different feed ratios of comonomers. Increasing the portion of DiPy in the comonomer mixture resulted in the formation of thinner and less rough copolymer films and to a modification of their morphology from a granular structure to a clover-like structure. In addition, copolymer films with very different conductivities were obtained by varying the comonomers ratio. Indeed, the conductivity of the copolymer containing 91% of Py was 2 × 105 times higher than the conductivity of the polymer containing 91% of DiPy, indicating that it is possible to tune the conductivity of the film by varying the composition of the initial comonomer mixture.