An X-state solid-liquid mixture with unusual mechanical properties formed by water and coordination polymer nanosheet...

Removal of water from a mixture of water and inorganic solids usually leads to a drastic change in the mechanical properties from liquid-like to brittle solid type. Here, we demonstrate that there is an unusual state, the X state, formed by naturally drying up a dough which is composed of Ni(H₂O)₂[(Ni(CN)₄]·H₂O nanosheets and water. This X-state mixture shows mechanical characteristics different from both pure liquids and brittle solids. The deformation curve of the X-state mixture contains three linear parts. However, the deformation is recoverable because the deformation curve can be repeated as long as fracture does not occur. The ice-like water formed among the nanosheets is believed to be an important reason for generating this X-state mixture. The unique properties of the X-state mixture may find applications, such as impact absorbents, which require materials with considerable strength, modulus and toughness.