Quantifying Defect Formation in Swollen Vitrimer Networks as a function of Chain Overlap

Vitrimers as dynamic covalent networks are known to respond to stimuli such as mechanical stress, and exhibit terminal relaxation behavior. In contrast, a permanent network exhibits no such relaxation. This difference leads to an interesting conundrum when comparing the swelling of dynamic covalent networks and their permanent counterparts. In a permanent network, the flux of solvent into the gel is eventually halted by the elastic penalty of deforming the network. Within a vitrimer system, the dynamic bond exchange may allow this elastic penalty to be relaxed away through the formation of defects such as loops, allowing more solvent to enter, potentially creating a feedback loop which ends with dissolution of the vitrimer. In this talk we present results from coarse-grained molecular simulations which monitor defect formation during the swelling process of a model dynamic covalent network and demonstrate how the equilibrium number of defects may be expressed as a simple function of the polymer concentration and extent of overlap between chains.