"Since current magnetic recording technology has a spatial resolution below 10 nm, it offers inexpensive and reprogrammable templating that can be used to build large-scale materials containing precisely positioned nanoparticles," said principal investigator, Thomas M Crawford, who helped to develop the pattern transfer process.

First, the researchers prepare a ferrofluid – a suspension of magnetic nanoparticles in a liquid – which is then used to coat the disk surface. Nanoparticles are pulled to the surface by the force of the magnetic field that is emitted from individual "bits" on the disk. After the nanoparticles assemble, the fluid is removed and the disk surface is coated with an air-curable liquid polymer.

Once cured, the solid polymer can be peeled from the disk to yield a transparent and flexible film containing the patterned nanoparticles. Applications include uses in optics and biotechnology, as well as novel materials technologies enabled by combining the customizable properties of nanoparticles with user-programmable long-range patterning.

Full details can be found in the journal Nanotechnology.