Theoretical Modelling of Vitrimers: Structural Evolution and Rheology

Vitrimers, a term coined by Leibler and his colleagues in the early 2010s, have a constant number of crosslinks regardless of the fact that the network structure can be dynamically rearranged, and their viscosity responds to the temperature in the form of the Arrhenius law as in the vitrification process of silica. Apart from the silica-like viscosity response, vitrimers can exhibit very rich rheological properties, due to the dynamic feature of the crosslinks. In this chapter, we present our theoretical modelling of such materials, with the microscopic crosslink dynamics incorporated in a continuum theory, which can be applied to analyse the rheological properties of vitrimers, including linear viscoelasticity, stress relaxation, creep compliance, stress responses in ramp deformations, etc. Moreover, the theory can be easily generalised to describe the rheology of other vitrimer-derived materials such as exchangeable liquid crystal elastomers.