Explaining the low-frequency shear elasticity of confined liquids
Abstract
Experimental observations of unexpected shear rigidity in confined liquids, on very low frequency scales on the order of 0.01 to 0.1 Hz, call into question our basic understanding of the elasticity of liquids and have posed a challenge to theoretical models of the liquid state ever since. Here we combine the nonaffine theory of lattice dynamics valid for disordered condensed matter systems with the Frenkel theory of the liquid state. The emerging framework shows that applying confinement to a liquid can effectively suppress the low-frequency modes that are responsible for nonaffine soft mechanical response, thus leading to an effective increase of the liquid shear rigidity. The theory successfully predicts the scaling law G ′ ∼ L − 3 for the low-frequency shear modulus of liquids as a function of the confinement length L , in agreement with experimental results, and provides the basis for a more general description of the elasticity of liquids across different time and length scales.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 03, 2020
- Source ID
- 10.1073/pnas.2010787117
Entities
People
- Alessio Zaccone
- Kostya Trachenko
Organizations
- Army Research Office
- Queen Mary University of London
- University of Cambridge
- University of Milan