Coagulation of blood: influence of chemical reactions on rheological response

Constrained mixture models have been developed in the recent past to describe the mechanical response of blood clots. Most such models capture the formation and dissolution of clots by empirical relations. Here, an attempt is made to capture the variation in rheological material functions with progress of coagulation, within a unified framework for chemically reacting systems. Forms are chosen for the Helmholtz free energy and the rate of entropy production function, such that chemical and mechanical processes that occur during clot evolution are appropriately accounted for. The mechanical response of the clot is assumed to be viscoelastic. The process of clot evolution takes place at a constant physiological temperature which allows for the Helmholtz potential formulation. The model is calibrated and then checked using experimental data (from the literature) for oscillatory shear. A constrained mixture model is presented which accounts for the chemical kinetics of reactions which lead to the formation of clot, and the consequent change in rheological response during coagulation.