Temperature, elasticity and geometric effects in the decohesion of soft matter layers

Archive ouverte : Communication dans un congrès

Bellino, Luca | Cannizzo, Andrea | Florio, Giuseppe | Giordano, Stefano | Puglisi, Giuseppe | Pugno, Nicola,

Edité par HAL CCSD

International audience. The complicated macroscopic decohesion and desorption phenomena of layers of soft materials (rubberlike, biological or bio-inspired) are the counterpart of complex and rich phenomena at the microscale: evolution of the natural configurations, insurgence and propagation of cracks, interaction and compatibility of the deformation of different layers. At the same time, adhesion plays an important role in growing of biological systems such as in tumour growth and focal adhesion. Based on minimal fully analytical models, we analyse the roles of temperature, elasticity and geometry in the decohesion process in several examples of interest in materials science and biological phenomena. We study the energetic competition between entropic energy terms, the elastic energy of the adhering layer and of the external device (AFM, interacting cell or proteins) regulating the decohesion phenomenon. We obtain the expressions of the strength, stiffness, decohesion energy and limit stretch as a function of microscale material properties evidencing the strong influence on ductility, toughness and force thresholds. We illustrate the effectiveness of the obtained models, by comparing the theoretical behaviour with the decohesion response of biological and bioinspired materials [1]. Moreover, we consider an extension of this class of models including also a damage mechanism, before decohesion, describing typical observations when connecting links (for instance, fibrils) can undergo a softening anticipating breaking. The model predicts a phase transition at a given critical temperature, corresponding to the complete detachment of the chain without mechanical actions [2].REFERENCES[1] G. Florio et al., Phys. Rev. Res. 2, 033227 (2020); G. Florio et al., in preparation (2021).[2] A. Cannizzo et al., J. Phys. A, in press (2021).

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