Mass Spectrometer ChamberThe researches inadvertently discovered that they can write and erase on the surface of liquids – the method that could one day be applied to high-density data storage, making templates for etching silicon chips (photolithography) and a variety of other materials applications.

Peter Licence at the University of Nottingham, UK, and his colleagues were using mass spectrometry (MS) as part of their ultra-high-vacuum research on liquids that contain only ions – ionic liquids. The experiment was carried out at -85oC when the ionic liquid of interest – 1-ethyl-3-methylimidazolium ethylsulfate is in a frozen state. The chemists noticed that the particle beam from the spectrometer created a pattern of charge on the surface of a frozen ionic liquid. When ionic liquids solidify they loose their conductivity and become insulators, but when the ion beam bombards the solid sample surface it knocks electrons from the material, leaving positively charged lines that frozen liquid cannot dissipate. These patterns can be erased by liquefying that spreads out the charge, or by flooding the surface with low-energy electrons.

Presently the resolution of these patterns is on a micrometer scale but it can be significantly increased to 10 nanometers by focusing the particle beam. The reader might think that the low temperatures of current experiments could prevent this method from a wide-spread commercial application; however, the ionic “liquids” that are solid at room temperature could be used as successful.

Reference: “Rewritable Imaging on the Surface of Frozen Ionic Liquids” by Frank J. M. Rutten, Dr., Haregewine Tadesse, Peter Licence, Dr.
Angew. Chem. Int. Ed.

Digital Object Identifier (DOI): 10.1002/anie.200700144