Kinetic characterization of p-tert-butylcalix[4,8,12]arene functionalized gold electrode by electrochemical impedance spectroscopy

Kinetic characterizations of impedimetric sensors having as transducers gold electrodes and as recognizing elements p-tert-butylcalix[4,8,12]arene were accomplished. Calixarene membranes were first studied using contact angle measurements. These revealed that all membranes exhibited hydrophobic and rough behaviours. Besides, based on the Van Oss model, surface energy components were determined and the main difference for the basic energy component was related to the calixarene conformation where hydroxyl groups were pointing towards gold surface.Electrochemical impedance spectroscopy results were modeled by appropriate equivalent circuits for the aim of elucidating electrical properties of calixarene functionalized gold electrodes. As results, a fast ionic transfer took place for p-tert-butylcalix[4] based impedimetric sensor, and a slow ionic transfer occurred for both p-tert-butylcalix[8,12] based impedimetric sensors. These behaviours were well accommodated with potentiometric outcomes that were previously encountered.