Scientists unveil the microscopic structure–property relationship of metal–organic polyhedron nanocomposites using SANS
Monodispersed hairy nanocomposites with typical 2 nm (isophthalic acid)24Cu24 metal–organic polyhedra (MOP) as a core protected by 24 polymer chains with controlled narrow molecular weight distribution has been probed by imaging and scattering studies for the heterogeneity of polymers in the nanocomposites and the confinement effect the MOPs imposing on anchored polymers. Typical confined‐extending surrounded by one entanglement area is proposed to describe the physical states of the polymer chains. This model dictates the counterintuitive thermal and rheological properties and prohibited solvent exchange properties of the nanocomposites, whilst those polymer chain states are tunable and deterministic based on their component inputs. From the relationship between the structure and behavior of the MOP nanocomposites, a MOP‐composited thermoplastic elastomer was obtained, providing practical solutions to improve mechanical/rheological performances and processabilities of inorganic MOPs.
Scientists have successfully constructed well‐defined star nanocomposites have been with MOPs as cores and have been systemically explored, from morphologies to physical properties, and especially structures and properties of the polymer chains under confinement. Two main domains, the confined‐extending area and the entanglement area, in the microstructure of hairy NPs have been verified from scattering measurements. Owing to the confinement effect, the polymer segments in the two domains behave differently, contributing to unique thermal and rheological behaviors and prohibited solvent exchange properties. Inspired by the phenomenon of chain entanglement of hairy NPs, a MOP‐composited thermoplastic elastomer has been successfully prepared and is of desirable elasticity and processability.
These fundamental studies of the MOP composites accelerate the developments in the rational design of porous coordination framework with desired processabilities and mechanical/rheological/thermal performances.
The full publication can be found here: https://www.onlinelibrary.wiley.com/doi/full/10.1002/anie.201909241