Flow and fracture near the sol-gel transition of silica nanoparticle suspensions

TL;DR

This study investigates how silica nanoparticle suspensions transition from fracture to flow near the sol-gel point, revealing coexistence of behaviors and flow over cracks as the transition is approached.

Contribution

It provides new insights into the mechanical response evolution of colloidal suspensions near the sol-gel transition, highlighting hysteresis and flow-fracture coexistence.

Findings

Cracks disappear at a finite distance from the transition.

Hysteresis observed in the flow-fracture transition.

Flow over cracks increases near the transition.

Abstract

We analyze the evolution of the mechanical response of a colloidal suspension to an external tensile stress, from fracture to flow, as a function of the distance from the sol-gel transition. We cease to observe cracks at a finite distance from the transition. In an intermediate region where the phenomenon is clearly hysteretic, we observe the coexistence of both flow and fracture. Even when cracks are observed, the material in fact flows over a distance that increases in the vicinity of the transition.