Competitive adsorption and threading behavior in cyclic-linear polymer blend films supported on an attractive substrate

Abstract

Cyclic polymers exhibit distinctive chain conformations and interfacial behaviors different from their linear counterparts, owing to their unique topological features. In this work, we employ molecular dynamics simulations to systematically investigate competitive adsorption and threading phenomena in cyclic-linear polymer blend films supported on an attractive substrate. By analyzing the dynamic evolution of the adsorption process, we demonstrate that cyclic chains are preferentially adsorbed over linear chains owing to their lower entropic penalty upon substrate attraction. Moreover, the mean square radius of gyration of cyclic chains, both in the adsorbed layer and in the bulk region, increases as the fraction of cyclic chains decreases, that is attributed to the effect of linear chains threading through cyclic chains. Simulation results further reveal that the competitive adsorption ability of cyclic chains is enhanced by increasing their stiffness, and the adsorbed cyclic chains adopt a flattened, rubber band-like conformation on the substrate at higher stiffness. This study elucidates the intricate interplay among topology, chain threading, and stiffness in governing the interfacial behavior of cyclic-linear polymer blends, offering valuable insights for the design of functional polymer films.