[nanoPost] NEWS ITEM: Nanowire mat for cleaning up oil

US researchers have developed a nanowire mat with the touch and feel of paper with potential for the clean-up of oil spills or for water filtration.

The hydrophillic "nanopaper," being developed at Massachusetts Institute of Technology (MIT)  is very similar to traditional writing paper.

Unlike normal writing paper, which is made from cellulose, nanopaper is made from solid potassium manganese oxide nanowires. Each nanowire is about 20 nanometres in diameter, and together they naturally clump together to form strands several centimetres long.

After being dissolved in water, the nanowires dry rapidly to create a sheet of nanopaper.

By itself, the nanopaper sucks up water just like normal paper. But by coating the nanopaper with siloxane vapour, a common polymer, the researchers turned it from a super hydrophilic material into a super hydrophobic material, repelling water while attracting oil.

The oil is soaked up and stored in the microscopic nooks and crannies between the individual nanowires, known as capillaries.

The combination of the nanowires and the polymer coating helps the nanopaper absorb oil.

After an oil spill, workers would lay the paper in the contaminated area. In areas of heavy contamination, the nanopaper would be saturated with oil in about five minutes.

The nanopaper would then be collected and boiled. The oil would be re-captured and the nanopaper re-used.

The MIT team has patented their nanopaper and plans to commercialise it.

The researchers estimates that it will be available in a year and a half and will cost about US$4 (A$4.18) per kilogram.