Hydrogen Bonding Effects on the Reversible Reorganization of Organic Films Electrografted on Glassy Carbon Electrodes

Daniel Morales‐Martínez; Felipe J. González

Index: 10.1002/celc.201800148

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Abstract

The electrochemical oxidation of tetrabutylammonium carboxylates derived from 6‐oxoheptanoic acid and 6‐heptynoic acid was performed on glassy carbon electrodes to generate covalently modified electrodes bearing alkyl‐ketone and alkynyl groups. These surfaces were used as models of hydrogen‐bond‐accepting surfaces to study the interaction of water with the grafted film; 1,4‐benzoquinone was used as the redox probe to demonstrate the existence of these interactions. The voltammetric behavior of this redox probe on the modified electrode changed during cycling. However, leaving this electrode to stand in the electrolyte solution allows the recovery of the starting voltammogram. These changes observed between cycling and stand time are cyclical and can be explained through a reversible reorganization effect of the grafted film, which is attributed to hydrogen bonding interactions between the functional groups present in the structure film and water present in the solvent. Supporting these surface effects, the switching behavior was absent on hydrophobic films formed with saturated aliphatic chains or by using ferrocene as non‐hydrogen bonding redox probe.