Stiffening solids with liquid inclusions
By Robert Style, R. Boltyanskiy, B. Allen, K. Jensen, Henry P. Foote, J. Wettlaufer, E. Dufresne. Nature Physics, 2014
315 citations recorded by the source corpus.
From bone and wood to concrete and carbon fibre, composites are ubiquitous natural and synthetic materials. Eshelby’s inclusion theory describes how macroscopic stress fields couple to isolated microscopic inclusions, allowing prediction of a composite’s bulk mechanical properties from a knowledge of its microstructure. It has been extended to describe a wide variety of phenomena from solid fracture to cell adhesion. Here, we show experimentally and theoretically that Eshelby’s theory breaks down for small liquid inclusions in a soft solid. In this limit, an isolated droplet’s deformation is strongly size-dependent, with the smallest droplets mimicking the behaviour of solid inclusions. Furthermore, in opposition to the predictions of conventional composite theory, we find that finite concentrations of small liquid inclusions enhance the stiffness of soft solids. A straightforward extension of Eshelby’s theory, accounting for the surface tension of the solid–liquid interface, explains our experimental observations. The counterintuitive stiffening of solids by fluid inclusions is expected whenever inclusion radii are smaller than an elastocapillary length, given by the ratio of the surface tension to Young’s modulus of the solid matrix. These results suggest that surface tension can be a simple and effective mechanism to cloak the far-field elastic signature of inclusions. Solids embedded with fluid inclusions are intuitively softer than their pure counterparts. But experiments show that when the droplets are small enough, material can become stiffer—highlighting a role for surface tension.
Subfields: Materials Chemistry, Mechanics of Materials, Polymers and Plastics
View Paper: https://www.semanticscholar.org/paper/4dd59d67842ee5c39da272690b63271deae4d58d
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In Materials Chemistry
Citations in the corpus
- Mechanical and Functional Tradeoffs in Multiphase Liquid Metal, Solid Particle Soft Composites (2018, background): “[42, 43] These properties suggest great promise for LM-elastomer composites in the application of soft materials in new areas of flexible system technologies.”