Creep and Fracture of a Protein Gel under Stress

Mathieu Leocmach , Christophe Perge (1) , Thibaut Divoux (2) , Sébastien Manneville (1)

1 Phys-ENS - Laboratoire de Physique de l'ENS Lyon
2 CRPP - Centre de recherches Paul Pascal

Biomaterials such as protein or polysaccharide gels are known to behave qualitatively as soft solids and to rupture under an external load. Combining optical and ultrasonic imaging to shear rheology we show that the failure scenario of a protein gel is reminiscent of brittle solids: after a primary creep regime characterized by a power-law behavior whose exponent is fully accounted for by linear viscoelasticity, fractures nucleate and grow logarithmically perpendicularly to shear, up to the sudden rupture of the gel. A single equation accounting for those two successive processes nicely captures the full rheological response. The failure time follows a decreasing power law with the applied shear stress, similar to the Basquin law of fatigue for solids. These results are in excellent agreement with recent fiber-bundle models that include damage accumulation on elastic fibers and exemplify protein gels as model, brittlelike soft solids.

Mots clés: Rheological aspects; Material behavior; Physical gels and microgels; Biopolymers biopolymerization; numbers: 8235Pq; 4757Qk; 8360-a; 8380Kn

Domaines: Matière Condensée [cond-mat]

Mathieu Leocmach, Christophe Perge, Thibaut Divoux, Sébastien Manneville. Creep and Fracture of a Protein Gel under Stress. Physical Review Letters, 2014, 113 (3), pp. 038303 (1-5). ⟨10.1103/PhysRevLett.113.038303⟩. ⟨hal-01147330⟩