Microstructural Convergence of Subnetworks in Reversibly Interlocked Polymer Networks Revealed by Small-Angle Neutron Scattering

Reversibly interlocked polymer networks (RILNs) have emerged as a versatile platform technology for the development of advanced functional materials. This is achieved by integrating two chemically independent subnetworks through supposition and cooperation principles. However, their physical image and the structure–property relationships remain unclear due to the undisclosed distribution of the subnetworks. In this study, a specially designed RILN system is synthesized, where the two component subnetworks exhibit distinct microstructures in their single network states. Moreover, one subnetwork is labeled with deuterons. The microstructures of the subnetworks in the interlocked state are examined using small-angle neutron scattering experiments based on the contrast-matching method. The deuterated subnetwork, which is homogeneous prior to interlocking, displays a heterogeneous microstructure in the RILNs like the nondeuterated subnetwork. Conversely, the nondeuterated subnetwork, which exhibits segmental aggregation before joining the RILNs, becomes homogenized in the interlocked state. These findings demonstrate the convergence of microstructures of the subnetworks, contributing to a better understanding of the physical image of the RILNs and enhancing our comprehension of their structure–property relationships.