Elastic deformations of loaded core-shell systems

TL;DR

This paper uses linear elasticity theory to analyze how spherical core-shell systems deform under radial forces, revealing the influence of material properties and coupling on their overall shape, with applications from macroscopic models to colloidal particles.

Contribution

It provides a detailed theoretical analysis of deformations in core-shell systems considering various material parameters and coupling effects, bridging macroscopic and mesoscale models.

Findings

Deformation depends on radii, stiffness, and Poisson ratio of core and shell.

Coupling between shell and core influences overall deformation shape.

Results applicable to both macroscopic models and colloidal microgels.

Abstract

Macroscopic elastic core-shell systems can be generated as toy models to be deformed and haptically studied by hand. On the mesoscale, colloidal core-shell particles and microgels are fabricated and investigated by different types of microscopy. We analyse, using linear elasticity theory, the response of spherical core-shell systems under the influence of a line density of force that is oriented radially and acts along the equator of the outer surface. Interestingly, deformational coupling of the shell to the core can determine the resulting overall appearance in response to the forces. We address various combinations of radii, stiffness, and Poisson ratio of core and shell and illustrate the resulting deformations. Macroscopically, the situation could be realized by wrapping a cord around the equator of a macroscopic model system and pulling it tight. On the mesoscale, colloidal microgel particles symmetrically confined to the interface between two immiscible fluids are pulled radially outward by surface tension.