Modulation of proton conductivity in coordination polymer mixed glasses

Reversible solid-to-liquid phase transition in coordination polymer glasses allowed the formation of homogeneous mixed-glasses from two distinct parent compounds. The resulting mixed glasses show composition-dependent glass transition temperatures and unique viscoelastic behaviour. A non-linear mixed glass former effect and controllable anhydrous H⁺ conductivities are also demonstrated.

Coordination polymer-forming liquid Cu(2-isopropylimidazolate)

The structure of the melt state of one-dimensional (1D) coordination polymer crystal Cu(isopropylimidazolate) (melting temperature T_m = 143 °C) was characterized by DSC, variable temperature PXRD, solid-state NMR (SSNMR), viscoelastic measurements, XAS, and DFT-AIMD calculations. These analyses suggested “coordination polymer-forming liquid” formation with preserved coordination bonds above T_m. Variable chain configurations and moderate cohesive interaction in adjacent chains are the keys to the rarely observed polymer-forming liquid. The melt structure is reminiscent of the common 1D organic polymer melts such as entanglement or random coil structures.

The melt state of coordination polymer crystals is composed of macromolecular-chain assemblies without coordination bond breaking. The coordination-polymer-forming liquid provides various morphologies, including spun fibers.

Alloying One-Dimensional Coordination Polymers To Create Ductile Materials

The preparation of coordination polymer (CP) alloys is demonstrated by the use of two meltable, one-dimensional crystal structures via melt-kneading. The polymer structures of the alloys are studied by synchrotron X-ray absorption and scattering, solid-state NMR spectroscopy, DSC, and viscoelastic measurements. Crystalline and amorphous domains and thermal properties (melting and glass transition) in the alloys depend on the ratio of the two constituent CPs. The glassy alloy composed of an equivalent amount of two CPs shows high plastic deformation properties, and the fracture point reaches 128% without a filler or compatibilizing agent, hence behaving as ductile materials.