Biofouling occurs through the attachment of biomolecules and microorganisms, such as bacteria, mussels, barnacles, algae, and seaweed, onto ship hulls. Such adhesion increases the hydrodynamic drag on vessels' sailing while causing pitting and crevice corrosion of vessels' metal surfaces. A biofouling-resistant coating—which is nontoxic, eco-friendly, and effective in different marine environments—is highly desired to minimize the biofouling effects. The zwitterionic trimethylamine-N-oxide (TMAO) is an emerging anti-biofouling material to this end. Employing quantum and atomistic molecular dynamics simulations, we investigated TMAO-hydration and its dynamics in the presence of ions, including TMAO's anti-biofouling efficacy. Our quantum dynamics simulations showed that the negatively charged oxygen atom of TMAO forms hydrogen bonding with surrounding water molecules, whereas the positively charged nitrogen atom, which is shielded by three methyl groups, exhibits non-hydrogen bond interactions with hydration water. We further studied the hydration governing non-covalent interactions, particularly electrostatic interactions between TMAO and hydration water. More quantitative analyses of hydrogen strength, polarization, charge transfer between TMAO and a Na<sup>+</sup> ion, and the polymer coating surface's water structure were performed. In addition, our atomistic MD simulations showed that the hydration of TMAO plays a key role in its antifouling capability against marine biofoulers, e.g., barnacle protein.

Quantum and atomistic molecular dynamics simulations of zwitterionic TMAO’s hydration and anti-biofouling

ACS Spring Meeting 2021

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