Monte Carlo simulations on thermodynamic and conformational properties of catenated double-ring copolymers

Abstract

The thermodynamic and conformational properties of catenated double-ring A-B copolymer melts are investigated through lattice Monte Carlo simulations. The topological constraint on the catenated copolymers is shown to suppress demixing of A and B monomers. This action results in their order-to-disorder transition (ODT) at an increased segregation level and the lamellae below ODT with reduced order, when compared to diblock copolymers of linear or single-ring topology. The A and B rings are pulled closer by catenation in the copolymer, which leads to its smaller gyration radius, lamellar domain spacing, and distance between mass centers of the two rings than for the diblock copolymers. With increasing segregation tendencies, the gyration radii of the A rings of the catenated copolymers stretch along the direction normal to lamellae, while the A-block conformations of the single-ring copolymers change their shapes from ellipsoid to sphere.

Domain Spacing and Composition Profile Behavior in Salt-Doped Cyclic vs Linear Block Polymer Thin Films: A Joint Experimental and Simulation Study

“…Several groups have established that A–B cyclic BPs show a 5–10% reduction in domain spacing relative to analogous A–B–A triblock polymers and an ∼40% reduction relative to A–B diblocks. − In addition to decreases in domain spacing, these studies demonstrated increases in interfacial curvature, decreases in order–disorder transition temperature, and weaker scaling with molecular weight for cyclic BPs in comparison to linear BPs. These findings agreed qualitatively with theory − and Monte Carlo simulations − that suggested similar trends in domain spacing, molecular weight scaling, and critical segregation strength for phase separation in cyclic BPs. All of the above work examined cyclic BP phase behavior in the bulk, and corresponding thin film studies must be completed to advance cyclic BPs in nanotemplating applications.…”

Polycatenanes: synthesis, characterization, and physical understanding

“…This is an interesting architecture as it can be thought of as two permanently entangled polymers and, as such, offers a model for studying the physical principles of polymer entanglements. 17,18 Polymers can also be accessed in which the entire architecture is composed of only interlocking rings (Fig. 1e-g).…”

“…This is an interesting architecture as it can be thought of as two permanently entangled polymers and, as such, offers a model for studying the physical principles of polymer entanglements. 17,18…”