Molecular dynamics simulations of the mechanical properties of dissociative dynamic bond elastomers with different binding-site sequences

Abstract

Dynamic bond elastomers are attracting attention because of their self-healing properties and toughness. However, understanding the factors that influence their mechanical properties remains challenging because their unique crosslinking structures lead to properties that are not well explained by classical rubber elasticity theory. This study utilized coarse-grained molecular dynamics simulations to investigate the effects of the one-dimensional sequence of binding sites and reaction time prior to elongation on the mechanical properties of dissociative dynamic bond elastomers. Uniaxial elongation simulations of systems with random and regular sequences revealed the existence of kinetically and thermodynamically controlled crosslinking structures depending on the reaction time. Notably, elastomers with a regular sequence and shorter reaction time displayed a higher modulus, which was attributed to an increased ratio of interchain crosslinks to total crosslinks. These findings offer novel insights into the structural determinants of the mechanical behavior of dynamic bond elastomers. Dynamic bond elastomers are attracting attention because of their self-healing properties and toughness. Using coarse-grained molecular dynamics simulations, we studied how the sequence of binding sites and reaction time before elongation affect their mechanical properties. Our simulations with random, regular, and semiregular sequences indicated that reaction time influences the formation of crosslinking structures. Elastomers with a regular sequence and shorter reaction time had a higher modulus due to more interchain crosslinks. These findings provide new insights into the mechanical behavior of dynamic bond elastomers.