The accumulation of microorganisms on the surface is a challenge for both the shipping and biomedical industries.Some popular anti-pollution polymer coatings undergo oxidative degradation in seawater, making them ineffective over time.Amphoteric ion (molecules with negative and positive charges and a net charge of zero) polymer coatings, similar to carpets with polymer chains, have attracted attention as potential alternatives, but currently must be grown in an inert environment without any water or air.This prevents them from applying to large areas.
A team led by Satyasan Karjana at the A*STAR Institute of Chemical and Engineering Sciences has discovered how to prepare amphoteric polymer coatings in water, room temperature and air, which will enable them to be used on A much wider scale.
“It was a serendipitous discovery,” explains Jana.His team was trying to make amphoteric polymer coatings using a widely used method called atom transfer radical polymerization, when they realized that some reactions did not produce the desired product.An amine was found unexpectedly at the end of the polymer chain as a ligand on the catalyst used in the reaction.”It will take some time and a series of experiments to unravel the mystery [of how it got there],” explains Jana.
Kinetic observations, nuclear magnetic resonance spectroscopy (NMR) and other analyses indicate that amines initiate polymerization through anion mechanisms.These so-called anionic polymerizations are not resistant to water, methanol, or air, but Jana’s polymers grew in the presence of all three, leading the team to doubt their findings.They turned to computer models to see what was happening.
“Density functional theory calculations confirm the proposed anionic polymerization mechanism,” he said.”This is the first ever example of an anionic solution polymerization of ethylene monomers in an aqueous medium under ambient aerobic conditions.”
His team has now used this method to synthesise polymer coatings from four amphoteric monomers and a number of anionic initiators, some of which are not amines.”In the future, we will use this method to create biofilt-resistant polymer layers on large surface areas using spray or impregnation methods,” Jana says.They also plan to study the antifouling effects of the coatings in Marine and biomedical applications.
Post time: Mar-18-2021