Negative linear compressibility in common materials

Abstract

Negative linear compressibility (NLC) is still considered an exotic property, only observed in a few obscure crystals. The vast majority of materials compress axially in all directions when loaded in hydrostatic compression. However, a few materials have been observed which expand in one or two directions under hydrostatic compression. At present, the list of materials demonstrating this unusual behaviour is confined to a small number of relatively rare crystal phases, biological materials, and designed structures, and the lack of widespread availability hinders promising technological applications. Using improved representations of elastic properties, this study revisits existing databases of elastic constants and identifies several crystals missed by previous reviews. More importantly, several common materials—drawn polymers, certain types of paper and wood, and carbon fibre laminates—are found to display NLC. We show that NLC in these materials originates from the misalignment of polymers/fibres. Using a beam model, we propose that maximum NLC is obtained for misalignment of 26°. The existence of such widely available materials increases significantly the prospects for applications of NLC.

Chemically driven negative linear compressibility in sodium amidoborane, Na(NH2BH3)

“…The magnitude of NLC can be compared by means of isothermal compressibilities K NLC = (∂lnl/∂p) T , defined in terms of the relative rate of change of length ‘l’ with respect to pressure. Further on our calculations demonstrate this material exhibits strong NLC with the magnitude K NLC = −7.9(5) TPa −1 which is almost twice as much as values reported for the majority of materials with NLC 1 2 3 . Abnormal compressibility of NaAB is quite unexpected as its crystal structure reveal no characteristic feature, e.g., tilting/rotating polyhedra networks, helices, specific framework topologies – typically shared by known materials with NLC.…”

“…Despite the counterintuitive character the phenomenon does not violate basic thermodynamic principle of overall volume reduction under pressure and may lay foundation for development of effectively incompressible materials for various practical applications, including materials for artificial muscles, amplification of piezoelectric response in sensors and actuators, tunable sieves for filtration, “smart” body armor made of robust shock absorbing materials, sensitive pressure detectors, materials used at deep sea, etc. The most significant challenges in this field have been the apparent rarity of materials showing NLC, the extreme weakness of the NLC effect found in these materials and little understanding of mechanisms governing NLC in particular materials 1 2 3 . Examples of NLC were reported in extensive inorganic (or organic), metal-organic as well as molecular framework materials 4 5 6 7 .…”

High-Pressure High-Temperature Structural Properties of Urea

“…0 the cell volume at ambient pressure, B 0 and C 0 are the isothermal bulk modulus and its derivative against pressure at p = 0, respectively. Contrary to what reported for phases I26,27 and III,26 a positive linear compressibility in all the crystallographic directions is here observed for phase IV.The coincidence of phases II and IV was further investigated by single crystal experiments. The P-T region indicated by Bridgman as pertaining to phase II was reached by two different P-T paths.…”

3D cellular models with negative compressibility through the wine‐rack‐type mechanism

“…Recently, Cairns and Goodwin reviewed the phenomenology of negative compressibility in multifarious materials and presented a mechanistic understanding of negative compressibility. Miller et al identified several relatively common materials which displayed NLC and presented several potential applications.…”