Giant Negative Compressibility by Liquid Intrusion into Superhydrophobic Flexible Nanoporous Frameworks

Materials or systems demonstrating negative linear compressibility (NLC), whose size increases (decreases) in at least one of their dimensions upon compression (decompression) are very rare. Materials demonstrating this effect in all their dimensions, negative volumetric compressibility (NVC), are exceptional. Here, by liquid porosimetry and in situ neutron diffraction, we show that one can achieve exceptional NLC and NVC values by nonwetting liquid intrusion in flexible porous media, namely in the ZIF-8 metal-organic framework (MOF). Atomistic simulations show that the volumetric expansion is due to the presence of liquid in the windows connecting the cavities of ZIF-8. This discovery paves the way for designing novel materials with exceptional NLC and NVC at reasonable pressures suitable for a wide range of applications.

Automated summary

This study demonstrates exceptional negative linear compressibility (NLC) and negative volumetric compressibility (NVC) values can be achieved through nonwetting liquid intrusion in flexible porous media, particularly in the ZIF-8 metal-organic framework. The presence of liquid in the windows connecting cavities of ZIF-8 leads to volumetric expansion, paving the way for designing novel materials with exceptional NLC and NVC at reasonable pressures for a wide range of applications.