Micromechanics of gel rupture – GelBreak
A gel is a soft solid composed of two intertwined phases: a solid network and a liquid solvent. The rupture of these soft heterogeneous materials is not well understood despite its importance in the mouth feel - thus the success - of most food industry products, as well as the lifetime of next-generation articular prosthesis. In order to elaborate new strategies to engineer the yielding behaviour of gels, we need a better comprehension of their rupture at the microscopic level. In particular we want to understand where and how is dissipated the energy injected from an external mechanical stimulus to be able to tune the delay before yielding.
Our strategy consists in upscaling the problem by using colloidal gels made of large particles so that the elementary processes of rupture will become directly visible to optical microscope. These model systems will be extremely soft, therefore we have to design an apparatus to apply controlled low mechanical stress while allowing microscopic 3D observation of the gel structure by confocal microscopy. We will use two colloidal systems: one with perfectly controlled interactions to understand internal stress distribution and evolution; a second from the food industry that more closely mimic protein gels and is closer to applications. We will first understand how delayed yielding plays out at particle level in our model system, then compare with the more realistic gel and, after a modelling step, we will finally look for ways to control the dissipation.
Our results could help formulate food gels in order to engineer their mechanical behaviour and thus replace resource intensive animal proteins by sustainable plant proteins while keeping the same mouth feel of the final product. At the fundamental level, our results could be extrapolated to polymer gels to allow them to resist to extreme solicitations in vivo, e.g. as cartilage replacement.
Monsieur Leocmach Mathieu (Institut Lumière Matière)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
ILM - CNRS Institut Lumière Matière
Help of the ANR 220,071 euros
Beginning and duration of the scientific project: - 48 Months