How to separate nanoparticles by "shape"

Physicists develop new strategy to separate molecules In our daily lives, the purpose and function of an item is defined by either its material, e.g. a rain jacket is fabricated of water-proof material, or its shape, e.g. a wheel is round to enable a rolling motion. What is the impact of the two factors on the nanoscale? The impact of material, i.e. the chemistry of the building block, has been excessively varied and the impact on polymer properties investigated leading to new functional materials, as for example slush powders. On the contrary, the impact of 'shape' has not been elucidated yet, since we are lacking reliable shape-sensitive separation techniques. Scientists of the University of Vienna and the International School of Advanced Studies in Triest, have overcome this hurdle. The results were published recently in the journal Macromolecules. The researchers developed a strategy how to separate knotted ring polymers from unknotted ones. Polymers are long molecules, consisting of the periodic repetition of a building block called a monomer.