Speed-dependent ice bandings in freezing colloidal suspensions

TL;DR

This study investigates how the speed of freezing affects ice bandings in colloidal suspensions, revealing that particle packing density and interface undercooling are key factors influencing the phenomenon.

Contribution

It proposes a mechanism linking particle packing density and interface undercooling to the formation of speed-dependent ice bandings, supported by quantitative experiments.

Findings

Particle packing density decreases with increasing pulling speed.

Speed-dependent packing influences curvature undercooling of pore ices.

Dynamic interface undercooling explains the variation in ice banding thickness.

Abstract

Formation mechanism of speed-dependent ice bandings in freezing colloidal suspensions, of significance in frost heaving and materials science, remains a mystery. With quantitative experiments, we propose a possible mechanism of speed-dependent ice bandings by focusing on the particle packing density and dynamic interface undercooling. The particle packing density ahead of the freezing interface decreases with increasing pulling speeds, attributed to the speed-dependent packing of particles. Through affecting the curvature undercooling of pore ices, the speed-dependent packing of particles can be used to explain speed-dependent thicknesses of ice bandings. The dynamic interface undercooling was obtained to explore curvature undercooling of pore ices and quantitative details of transient interface positions, speeds and undercooling were given. All the evidences imply that the speed-dependent particle packing and dynamic interface undercooling are responsible for speed-dependent ice bandings.