"We wanted a polymer coating that is as versatile as a Swiss army knife."Nicholas Spencer, ETH Zürich

Coatings are regularly used make a surface slippery, in order to prevent algae, proteins or bacteria from fouling it over time, which can be a problem both underwater and within the body. Hydrophilic polymers are often used for this purpose: water molecules accumulate on the polymer layer, preventing molecules or organisms from adhering to the underlying material.

However, many coatings currently in use are not very resistant to environmental factors, since they are often only connected to the material by weak electrostatic bonds. Other, more robust coatings are often expensive and sometimes require toxic solvents.

So scientists led by Nicholas Spencer, professor of surface science and technology at ETH Zürich in Switzerland, together with researchers at the ETH spin-off Susos, decided to search for a simple way to bind coating molecules to surfaces with a strong covalent bond. They also wanted to find a solution that could be used to coat a range of surfaces and devices composed of several different materials. "We wanted a polymer coating that is as versatile as a Swiss army knife," says Spencer.

And that is just what the scientists succeeded in developing. As reported in Macromolecular Rapid Communications, they have produced a polymer that comprises a long backbone from which hydrophilic side chains branch out to impart non-fouling properties. The polymer also possesses two other types of side chains able to form covalent bonds – one can form bonds with silicon and glass, while the other can form bonds with oxides of transition metals such as titanium and iron.

"Coatings with our new polymer are very simple. It's just dip and rinse", says Spencer. "And the coating withstands even harsh conditions such as acids, alkalis, high salt concentrations and detergents."

The ETH spin-off Susos has submitted a patent application for the polymer. The scientists see possible applications for the coating mainly in biomedical diagnostics and medical technology, where it would be used to prevent microbes colonizing biosensors, implants and future implantable drug-delivery systems. Other applications could include biofouling prevention in water treatment, ship transport and fishing, as well as by the food industry, for example in packaging.

The ‘Swiss army knife’ in its current form is highly adaptable and opens the door to a host of further developments. As Spencer explains, it would be possible to equip the polymer's molecular backbone with side chains that bind to other materials, or to replace the side chains that prevent microbial adhesion with others that have totally different properties.

This story is adapted from material from ETH Zürich, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.