Investigation of Protective Properties of Organic Layers toward Reactive Oxygen Species

Abstract

The antioxidant protective properties of polyaromatic organic layers were evaluated towards Reactive Oxygen Species (ROS) using Scanning Electrochemical Microscopy (SECM) in a foot-printing strategy. The layers were prepared by electrografting of aryldiazonium salts. Where p-(methyl)phenyl films show only weak protective properties towards ROS, p-(ethynyl)phenyl films evidence an efficient protection of the covered surfaces. Applied potentials and electrolytes used during ORR are critical parameters to control, to prevent or reduce the influence of ROS production and hence enhancing devices lifetime.

Electrochemical grafting of aryl diazonium salts in deep eutectic solvents

“…They were synthesized as previously described. [30] The PPFs were typically 15 x 15 mm² and were cleaned in an ultrasonic bath in acetone, methanol and 2-propanol, and dried under Argon before use.…”

“…However, the maximum thickness values obtained are smaller than the one expected using these classical solvents. For example, the electroreduction of Eth-Ar-N 2 + BF 4 in acetonitrile leads to ethynylphenyl films with thickness of 6 to 7 nm [29,30] while I-Ar-N 2 + BF 4 electroreduction in acetonitrile leads to iodophenyl films of ~5 nm [24] which is 2.5 to 3 times thicker than in ethaline under similar electrochemical deposition conditions. Moreover, we observed that the thickness quickly reaches a plateau (after 120 s of electrolysis), suggesting a self-limiting growth process in the DES.…”