Nanobrush that repels dirt in the offing

Scientists have developed a new way to make "polymer nanobrush" -- bristly materials which prevent dust from accumulating on various surfaces.

Polymer brushes have been used to coat everything from eyeglass lenses, boats and medical devices -- where they keep away smudges, damaging chemicals and germs -- to artificial joints and mechanical components in vehicles where they act as a lubricant.

Developed by a team of engineers led by Christopher Li, professor at Drexel University's college of engineering in Philadelphia, it gives scientists a higher degree of control over the shape of the brush and bristles and is much more efficient.

"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," Li said.

His approach involves growing a functional two-dimensional sheet of polymer crystals -- similar to a nanoscale piece of double-sided tape. When the sheet is stuck to an existing substrate, and the crystals are dissolved, the remaining polymer chains spring up, forming the bristles of the brush.

"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," added Li in the study published in the journal Nature Communications.

The new brush is the most densely packed polymer brushes to date, with bristles less than a nanometre apart.

Polymer brush materials are especially useful in situations where pieces need to fit tightly together but need to be able to move without friction throwing a wrench in the works.

These are also effective for keeping important surfaces free of particles, chemicals, proteins and other fouling agents.