2020/12/17 by Angelo Pommella, Luca Cipelletti, Laurence Ramos · 15 citations
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · Chemical Engineering · Chemistry · Physics and Astronomy · #Biopolymer #Chemical physics #Chemistry #Composite material #Creep #Dynamics (music) #Fracture (geology) #Hydrogels: synthesis, properties, applications #Materials science #Mechanics #Physics #Plasticity #Polymer #Polysaccharides Composition and Applications #Relaxation (psychology) #Rheology #Rheology and Fluid Dynamics Studies #Shear (geology) #Stress (linguistics) #Stress relaxation #cond-mat.soft
paper · pdf · doi:10.1103/physrevlett.125.268006
published in Physical Review Letters 125(26), 268006 (American Physical Society) · accepted for publication in Physical Review Letters
arxiv created 2020/12/17 · openalex publication_date 2020/12/31 · arxiv updated 2021/01/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate the delayed rupture of biopolymer gels under a constant shear load by simultaneous dynamic light scattering and rheology measurements. We unveil the crucial role of normal stresses built up during gelation: All samples that eventually fracture self-weaken during the gelation process, as revealed by a partial relaxation of the normal stress concomitant to a burst of microscopic plastic rearrangements. Upon applying a shear stress, weakened gels exhibit in the creep regime distinctive signatures in their microscopic dynamics, which anticipate macroscopic fracture by up to thousands of seconds. The dynamics in fracturing gels are faster than those of nonfracturing gels and exhibit large spatiotemporal fluctuations. A spatially localized region with significant plasticity eventually nucleates, expands progressively, and finally invades the whole sample, triggering macroscopic failure.