Physicists show in a new study that periodically deforming a gel as it sets allows for precise control of its mechanical properties.

Are you one of those people who shake their yoghurt pot before opening it? Bad idea – or perhaps a brilliant one, depending on what you’re after! Yoghurt, like mayonnaise, toothpaste, fresh concrete or 3D printing inks, belongs to the large family of colloidal gels: soft solids formed by the aggregation of microscopic particles suspended in a liquid.

By attracting one another, these particles gradually form a percolated network that traps the liquid and gives the material its mechanical strength. This transition from liquid to solid, also known as the ‘sol-gel transition’, has been studied for decades… but almost always at rest, in the hushed comfort of laboratories.

In industrial reality, however, gels rarely form under such ideal conditions: they are poured, spread, extruded, or printed, while being subjected to mechanical deformations that can be significant. How do these perturbations influence the formation of the solid network? The question has remained surprisingly unexplored.

Learn more on the CNRS website

Reference

Imprinting macroscopic fracture during gelation: A mechanism for tuning colloidal gels. W.J. Smit et al. Physical Review Materials 10, 045602. Published on 03 April 2026.
DOI: 10.1103/ng2j-nrfv
Open archive: arXiv