How Does A Porous Shell Collapse? Delayed Buckling And Guided Folding Of Inhomogeneous Capsules

TL;DR

This paper investigates how inhomogeneities in colloidal capsule shells influence the timing and pathway of buckling under osmotic pressure, combining shell theory with Darcy's law for quantitative understanding.

Contribution

It introduces a coupled shell theory and Darcy's law framework to explain the effects of shell inhomogeneity on buckling delay and folding pathways in capsules.

Findings

Increased inhomogeneity shortens buckling delay.

Shell inhomogeneity alters folding pathways after buckling.

Quantitative model matches experimental observations.

Abstract

Colloidal capsules can sustain an external osmotic pressure; however, for a sufficiently large pressure, they will ultimately buckle. This process can be strongly influenced by structural inhomogeneities in the capsule shells. We explore how the time delay before the onset of buckling decreases as the shells are made more inhomogeneous; this behavior can be quantitatively understood by coupling shell theory with Darcy's law. In addition, we show that the shell inhomogeneity can dramatically change the folding pathway taken by a capsule after it buckles.