Bubbles enable volumetric negative compressibility in metastable elastocapillary systems

Abstract

Although coveted in applications, few materials expand when subject to compression or contract under decompression, i.e., exhibit negative compressibility. A key step to achieve such counterintuitive behaviour is the destabilisations of (meta)stable equilibria of the constituents. Here, we propose a simple strategy to obtain negative compressibility exploiting capillary forces both to precompress the elastic material and to release such precompression by a threshold phenomenon – the reversible formation of a bubble in a hydrophobic flexible cavity. We demonstrate that the solid part of such metastable elastocapillary systems displays negative compressibility across different scales: hydrophobic microporous materials, proteins, and millimetre-sized laminae. This concept is applicable to fields such as porous materials, biomolecules, sensors and may be easily extended to create unexpected material susceptibilities.

Partial Water Intrusion and Extrusion in Hydrophobic Nanopores for Thermomechanical Energy Dissipation

“…Furthermore, apart from compression–decompression cycles, the intrusion–extrusion in HLS can be achieved by heating–cooling cycles . This characteristic becomes suitable for developing thermal actuation applications or technologies. , Finally, intrusion–extrusion in HLS is also relevant for several other applications such as (i) chromatography, ,− (ii) negative compressibility, − (iii) triboelectric generators, , and (iv) biological systems. , …”

“… 34 This characteristic becomes suitable for developing thermal actuation applications or technologies. 21 , 35 Finally, intrusion–extrusion in HLS is also relevant for several other applications such as (i) chromatography, 29 , 36 − 100 (ii) negative compressibility, 39 − 101 (iii) triboelectric generators, 42 , 43 and (iv) biological systems. 44 , 45 …”