Topological symmetry breaking in viscous coarsening

TL;DR

This study investigates how hydrodynamic instabilities cause topological symmetry breaking during viscous phase separation, leading to distinct morphologies in different phases, using in-situ X-ray tomography of glass melts.

Contribution

It reveals the role of viscosity contrast in inducing symmetry breaking and phase-specific fragmentation during viscous coarsening, with experimental evidence across multiple compositions.

Findings

Viscosity contrast causes preferential breakup in the less viscous phase.

Distinct morphologies develop in the two phases due to symmetry breaking.

Fragmentation resembling end-pinching occurs in the less viscous phase.

Abstract

The crucial role of hydrodynamic pinch-off instabilities is evidenced in the coarsening stage of viscous liquids. The phase separation of a barium borosilicate glass melt is studied by in-situ synchrotron X-Ray tomography at high temperature. The high viscosity contrast between the less viscous phase and the more viscous phase induces a topological symmetry breaking: capillary breakups occur preferentially in the less viscous phase. As a result, contrasting morphologies are obtained in the two phases. This symmetry breaking is illustrated on three different glass compositions , corresponding to different volume fractions of the two phases. In particular, a fragmentation phenomenon, reminiscent of the end-pinching mechanism proposed by Stone et al. [1, 2] is evidenced in the less viscous phase.