Materials containing tiny capillaries and cavities are widely used in filtration, separation and many other technologies, without which our modern lifestyle would be impossible. Those materials are usually found by luck or accident rather than design. It has been impossible to create artificial capillaries with atomic-scale precision.

Now a Manchester group led by postdoctoral researcher Radha Boya and Nobel laureate Andre Geim show how to make the impossible possible, as reported in Nature.

The new technology is elegant, adaptable and strikingly simple. In fact, it is a kind of antipode of the famous material graphene. When making graphene, people often take a piece of graphite and use Scotch tape to extract a single atomic plane of carbon atoms, graphene. The remaining graphite is discarded.

In this new research, Manchester scientists similarly extracted a strip of graphene from graphite, but discarded the graphene and focused on what was left: an ultra-thin cavity within the graphite crystal.

Such atomic scale cavities can be made from various materials to achieve not only a desired size but also to choose properties of capillary walls. They can be atomically smooth or rough, hydrophilic or hydrophobic, insulating or conductive, electrically charged or neutral; the list goes on.

The voids can be made as cavities (to confine various substances) or open-ended tunnels (to transport different gases and liquids), which is of huge interest for fundamental research and many applications. It is limited only by imagination what such narrow tunnels with designer properties can potentially do for us.