New method for fabricating nanobrushes

Researchers from Drexel University in Philadelphia have developed a new technique for creating nanobrushes, tiny structures that coat surfaces and repel dirt.

Polymer nanobrushes have been used to coat everything from eyeglass lenses and the hulls of boats, to medical devices and artificial joints. Despite the name, they prevent particles from forming on surfaces in the first place rather than brushing them away.

Nanobrushes are used to coat eyeglass lenses (Credit: Frank C. Müller via CC)
Nanobrushes have been used to coat eyeglass lenses (Credit: Frank C. Müller via CC)

Until now, applying a coat of these structures has involved treating surfaces with solutions and waiting for the brushes to develop, or individually grafting the brushes. The new technique, described in Nature Communications, saw the researchers growing a functional two-dimensional sheet of polymer crystals, similar to a nanoscale piece of double-sided tape. This sheet is then applied to a substrate, the crystals are dissolved, and the remaining polymer chains spring up to form the bristles of the brush.

“The past few decades witnessed exciting progresses in studies on polymer brushes, and they show great promises in various fields, including coating, biomedical, sensing, catalysis to name just a few,” said Professor Christopher Li from Drexel’s College of Engineering.

“We believe that our discovery of a new way to make polymer brushes is a significant advance in the field and will enable use of the brushes in exciting new ways.”

As well as speeding up the application process, Li’s method can also control the formation of the two-dimensional crystal sheets, including how far apart they’re spaced. According to the paper, the researchers were able to creat the most densely packed polymer brushes to date, with bristles less than a nanometre apart.

“What this all means is that one day engineers will be able to tailor-make incredibly durable polymer brush coatings to extend the usage lives of all kinds of uniquely shaped joints and couplings,” said Li. “This shifts the way we look at making the brushes and I think it will have a lasting impact on this area of research.”