Macromolecular diffusion in dynamic cross-linked networks: From intrinsic physical properties to dynamics and transport

The diffusion behavior of macromolecules in dynamic cross-linked networks (DCNs) represents a core scientific issue linking the intrinsic physical properties of the network to mass transport processes. The inherent dynamism and heterogeneity of DCNs challenge classical diffusion theories and call for new theoretical frameworks. This review summarizes recent advances in understanding how reversible bonds mediate network topology reconstruction and thereby regulate diffusion. Particular emphasis is placed on the quantitative relationships between key physical parameters—such as mesh size, topology, bond exchange rate, and characteristic relaxation time—and the resulting diffusion dynamics, as well as on the coupling among different timescales, including bond lifetime, network relaxation, and diffusion. By integrating insights from theoretical modeling, simulations, and experimental studies, we highlight emerging principles that underpin the regulation of diffusion in DCNs. Finally, we identify the remaining open problems and key challenges for advancing the predictive understanding and control of diffusion in DCNs.