Fig. 2: Model of a metastable elastocapillary system exhibiting negative compressibility.
From: Bubbles enable volumetric negative compressibility in metastable elastocapillary systems
A Sketch of a thought intrusion and extrusion experiment in which (i) two plates (brown) kept together by a spring (black) of constant k and length a (equilibrium length a0) are immersed in water (ii), then the hydrostatic pressure p is progressively increased (iii) until intrusion occurs (iv). The pressure is subsequently decreased from the fully intruded state, until extrusion is achieved (vi) and the cycle can repeat. pa is the ambient pressure; \(\Delta {a}_{{{{{{{{\rm{NC}}}}}}}}}^{{{{{{{{\rm{int}}}}}}}}}\) and \(\Delta {a}_{{{{{{{{\rm{NC}}}}}}}}}^{{{{{{{{\rm{ext}}}}}}}}}\) are the negative compressibility jumps at intrusion and extrusion, respectively, and Δap and Δaγ denote the elastic compression and the capillary precompression contributions to such jumps, respectively, see main text. Blue lines represent the gas-liquid interface, with γ being the surface tension. B Representation of the cycle in the pressure–interplate distance plane. Grey dashed lines indicate the compression/decompression cycle for a simple solid material (non-MES).
