Electroactive Polyhydroquinone Coatings for Marine Fouling Prevention—A Rejected Dynamic pH Hypothesis and a Deceiving Artifact in Electrochemical Antifouling Testing

Abstract

Nanometer-thin coatings of polyhydroquinone (PHQ), which release and absorb protons upon oxidation and reduction, respectively, were tested for electrochemically induced anti-biofouling activity under the hypothesis that a dynamic pH environment would discourage fouling. Antifouling tests in artificial seawater using the marine, biofilm-forming bacterium Vibrio alginolyticus proved the coatings to be ineffective in fouling prevention but revealed a deceiving artifact from the reactive species generated at the counter electrode (CE), even for electrochemical bias potentials as low as |400| mV versus Ag|AgCl. These findings provide valuable information on the preparation of nanothin PHQ coatings and their electrochemical behavior in artificial seawater. The results further demonstrate that it is critical to isolate the CE in electrochemical anti-biofouling testing.

Conducting Copper(I/II)-Metallopolymer for the Electrocatalytic Oxygen Reduction Reaction (ORR) with High Kinetic Current Density

“…In this report, the authors describe the synthesis, characterization, and application of a novel copper-doped polymer, based on the PHAM structure. In addition to published PHAM structures, they introduced an electro-active quinone/hydroquinone moiety into the heteroarylene methine backbone [50,51,52], which provided a reversible two-electron redox response in a small potential window, thus expecting a four-electron redox response per repetition unit according to Scheme 1 [53,54,55].…”

Cyclic Copper Uptake and Release from Natural Seawater—A Fully Sustainable Antifouling Technique to Prevent Marine Growth

“…These results were observed within the same experimental tank, suggesting that no reactive oxygen and/or chlorine species were electrochemically accumulated over the 4 day experiment, as these would have inhibited the diatom growth on all coupons. 53 However, a significant decrease in growth was observed as the potential increased from 1.1 to 1.4 V vs Ag|AgCl, indicating inhibition of settlement at elevated water splitting and resulting copper release rates. This trend was clearly reflected in the plotted total number of diatoms counted on all SEM images at selected electrode potentials (Figure 3f).…”

Application of poly(vinylphosphonic acid) modified poly(amidoxime) in uptake of uranium from seawater

“…Briey, VPA was polymerized on the PAN surface by plasma technique, followed by amidoximation treatment. To evaluate the anti-biofouling properties and adsorption capability of PVPA/PAO, the well-known marine microorganism V. alginolyticus 11,25 was selected as a representative of marine microorganisms. The effects of environmental conditions were studied.…”