The world's cleanest water droplet
The 'molecular dirt' found on any surface can change the properties of the material. A new method has been developed to study this. By creating ultra-pure ice in a vacuum chamber and melting it the world's cleanest water drops were created and applied to titanium dioxide surfaces. The 'dirt' turns out to be a single-molecule-thick layer of two organic acids. This is surprising, because only minute traces of these acids are found in air.