Morphology and Dynamics of Catenanes in Dilute Solutions and at Liquid/Liquid Interface

Molecular Dynamics simulations are performed with all-atom poly (ethylene oxide) (PEO) and polystyrene (PS) structures in water and in toluene and at the water/toluene interface and the dynamics and structural properties of PEO and PS chains with different topologies such as linear, isolated rings and interlocked rings (homo and hetero catenation) are studied. This includes the comprehensive study of the effect of chain flexibility, solvent quality and interface as deterministic factors that influence the morphology and dynamics of the catenanes. The results can be exploited to design and fabricate molecules with desired dynamics and will be of particular significance for drug delivery applications. Our simulations predict larger radius of gyration and faster dynamics for flexible topologies in a good solvent. In a poor solvent, they shrink to smaller size and again diffuse faster compared to the rigid counterparts. Moreover, hydrogen bonding significantly affects the dynamics of the molecules in water both in bulk and at the interface. At the water/toluene interface, molecules develop a flat morphology and thus have larger size as compared to their coil structures in the bulk of a good solvent and are found to show faster diffusion.