Imaging crack propagation in tough model gels by ultrasound elastography*

Assessing biomechanical properties of soft tissues by ultrasound imaging is still a challenge to help physicians to characterize pathologies. Benefiting from the recent progress in the field, the idea is to develop a novel, non-invasive tool with a high time-resolution to understand crack propagation processes in synthetic model gels. This approach offers new insights into soft matter fracture.
This project focuses on the use of shear wave elastography for a local elasticity mapping at the vicinity of an advancing crack. Model polymer networks with well-controlled mechanical responses are synthetized following the protocol of Rose et al.[1]. By addition of silica nanoparticles (NPs), these gels combine a covalent polymer network (elasticity) with physical interactions by adsorption of polymer onto silica NPs (viscoelasticity) [2]. The gels are characterized in a wide range of frequencies in tensile mode (small strain rates) coupled with high frequency shear wave spectroscopy described by Deffieux et al.[3].

[1] Rose, Dizeux, Narita, Hourdet, Marcellan. Macromolecules, 2013
[2] Rose, Prevoteau, Elziere, Hourdet, Marcellan, Leibler. Nature, 2014
[3] Deffieux, Montaldo, Tanter, Fink. Trans. Med. Imaging, 2009