Nano networks exhibiting negative linear compressibility

Abstract

Molecular mechanics simulations were used to analyse the on-axis mechanical properties of a series of nanonetworks. These consisted of naphthacene-like units linked together through acetylene chains, and designed to mimic the geometry of a winerack-like structure in one of the major planes, a geometry which is closely associated with negative linear compressibility. It was found that these networks have a potential to exhibit a negative linear compressibility in one of the major axis. An analysis of the deformation mechanism as well as the magnitudes of the compressibility in the major directions suggest that this effect arises from relative rotations of the rigid polyphenyl chains and is comparable to that predicted by an idealised winerack model deforming through hinging. This confirms that there is a very strong link between negative linear compressibility and geometry, as is the case with auxetic materials.