3D volumetric rheometry of gel networks using optical coherence tomography and digital volume correlation

Optical coherence tomography (OCT) combined with digital volume correlation (DVC) is a powerful technique for investigating the microstructural and mechanical behavior of soft, heterogeneous materials such as gel networks. In this study, OCT and DVC are combined to measure full-field displacement and strain distributions in hydrogel subjected to stress-relaxation uniaxial tension. Measurement uncertainties and optimal OCT-DVC parameters are assessed to establish practical guidelines for similar analyses. The obtained OCT-DVC strain maps reveal heterogeneities in the viscoelastic properties, depending on local gel composition and crosslinking density. These results highlight the potential of the OCT-DVC technique for probing microscale mechanical behavior in gel systems and open new perspectives for studying deformation mechanisms in soft matter.