When a droplet of water is flattened between 2 sheets of graphene, a strange thing happens, a never before seen type of room temperature “square ice” appears. Ice typically forms 3D pyramids, but in “square ice”, they are locked flat, and at right angles.

This is yet another surprise from Andre Geim, who won a Nobel Prize in 2010 for his work on graphene and an Ignoble Prize in 2000 for levitating a frog. By putting a droplet of water between graphene sheets, and then pressing the them together, small pockets of square ice began to form. The discovery reveals yet another property of graphene, a 2D form of carbon. Its flat structure allows two sheets of graphene to exert van der Waals forces, pulling the two sheets together. Geim’s team estimates that the graphene sheets were able to exert over 10,000 atmospheres of pressure.

Geim’s team is now investigating possible uses, such as water filtration. This adds to the list of potential applications being explored for graphene, in fields as diverse as molecular biology, computer chips, and even radar invisibility cloaks.