Related Experiment Video
Updated: Apr 15, 2026

Author Spotlight: Shear Assay Protocol for the Determination of Single-Cell Material Properties
Published on: May 19, 2023
Shear-stress function approach of hydration layer based on the Green-Kubo formula
Bongsu Kim1, Soyoung Kwon1, Geol Moon1
1Center for THz-Bio Application Systems and Institute of Applied Physics, Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea.
Abstract:
We present the analytic expression of the stress correlation (SC) function for the ubiquitous hydration water layer (HWL) using the Green-Kubo equation and the shear modulus of HWL. The SC function is then experimentally obtained by measuring the viscoelastic properties of HWL using shear-mode dynamic force spectroscopy. Interestingly, the SC changes sign from positive to negative as the HWL thickness increases, where the shear stresses acting on the HWLs bound to two nearby surfaces are out of phase. We also suggest that the repulsive hydration force originates from the SC of HWL. Our results provide the first demonstration of the microscopic understanding of the HWL viscoelasticity and may allow a deeper insight on the HWL dynamics as well as the complex liquids.
Related Concept Videos
Shearing Strain
Generalized Hooke's Law
Components of Stress
Interestingly, the hidden cube faces also experience these stresses, equal and...
Transformation of Plane Stress
Shearing Stresses in a Beam: Problem Solving
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity

