The mechanics and structure of associative polymer networks are directly dependent upon the dynamic nature of the reversible crosslinks and chain segments, as these transient motifs allow for stress dissipation and network rearrangement. While this reversibility enables the design of self-healing soft materials, noncovalent networks are unstable and prone to creep as the network rearranges. Topological entanglements have been used to overcome these limitations and toughen physical polymer networks, enabling high extensibility and enhanced creep resistance. While the cooperativity between sticker association and topological entanglements is well understood to distribute and dissipate stress in a network, its effect to impede the motion of chains through a network remains poorly understood. To decouple the individual associative- and topological- contributions to single-chain diffusion, this work investigates the diffusion of an entangled, associative polymer network via coarse-grained Brownian dynamics simulations. In agreement with previous experiments, a long-term diffusive retardation and narrowing of the superdiffusive regime—where the mean square displacement exhibits a stronger time dependence than Fick’s law—is observed at elevated concentrations. While this suppression is largely governed by the global concentration of associative groups, entanglements serve as another constraint to impede the motion of freely-diffusing chains and reduce the step size of bound chain segments. These simulations also have revealed the presence of an additional segmental diffusive mode ascribed to the reptative motion of entangled strands. The magnitude by which entanglements slow this segmental relaxation is comparable to the extent of long-term deceleration observed in bulk, illustrating the direct connection that terminal diffusion is the culmination of collective segmental motions. These simulations provides valuable insight into the complex interplay between transient associations and topological entanglements which underly the mechanism of self-healing and creep resistance in entangled associative polymer networks.
