Reversible transformations in bulk polymers offer numerous possibilities for materials remodeling and reprocessing. While reversible systems based on dynamic covalent chemistry such as the Diels–Alder reaction and transesterification have been intensively studied to enable local bond dissociation and formation, reports regarding the reversion from bulk network polymers to monomers are rare. Herein, we report a reversibly polymerizable system based on ring-opening metathesis polymerization of cyclopentene derivatives in the bulk state. The network polymer is thermodynamically stable and mechanically robust at room temperature and readily depolymerizes at elevated temperatures to yield liquid monomers that are repolymerized to cross-linked polymers by simply cooling to room temperature. This reversible process was characterized by differential scanning calorimetry and rheological tests.

Extensional viscosity is a key property of complex fluids that greatly influences the non-equilibrium behavior and processing of polymer solutions, melts, and colloidal suspensions. In this work, we use microfluidics to determine steady extensional viscosity for polymer solutions by directly observing particle migration in planar extensional flow. Tracer particles are suspended in semi-dilute solutions of DNA and polyethylene oxide, and a Stokes trap is used to confine single particles in extensional flows of polymer solutions in a cross-slot device. Particles are observed to migrate in the direction transverse to flow due to normal stresses, and particle migration is tracked and quantified using a piezo-nanopositioning stage during the microfluidic flow experiment. Particle migration trajectories are then analyzed using a second-order fluid model that accurately predicts that migration arises due to normal stress differences. Using this analytical framework, extensional viscosities can be determined from particle migration experiments, and the results are in reasonable agreement with bulk rheological measurements of extensional viscosity based on a dripping-onto-substrate method. Overall, this work demonstrates that non-equilibrium properties of complex fluids can be determined by passive yet non-linear microrheology.

The ability of nanosegregated polymerized ionic liquids (PILs) to dissipate shockwave energy is investigated for a series of imidazolium-based PILs with varying alkyl spacer length. The PILs are designed to have similar glass transition temperatures but different structures. X-ray scattering analysis reveals that each of the amorphous PILs exhibit distinct nanoscale structural heterogeneity, depending on the length of the chain spacer. We find that a higher structural heterogeneity, determined from the intensity of the intercluster scattering peak, in the PILs with longer alkyl spacers results in greater shockwave energy dissipation. In addition, we observe the crystalline phase is less effective at dissipating shockwave energy than the amorphous phase due to the close packed morphology and slow kinetics.

This study examines the influence of culture on Chinese consumers' intentions to purchase Australian products. Data were obtained from an online survey completed by 3,171 respondents across 20 cities in China. Results indicate that ingroup influence, product perception, but not marketing efforts have a significant main effect on purchase intentions. In addition, ingroup influence moderates the effects of product perception and marketing efforts on intentions. When ingroup influence is low, product perception has a greater impact on purchase intention than when ingroup influence is high. Similarly, marketing efforts have a greater impact on purchase intention when ingroup influence is low than when it is high. In addition, self-identity as a consumer of imported products also moderates the strength of association between product perception and purchase intention. When self-identity is low, product perception has a greater impact on purchase intention than when self-identity is high. Implications of the findings for theory and practice, in the context of trade between an individualistic culture like Australia and a collectivistic one like China, are discussed.

An attempt at expanding the family of f-element bearing TPTZ coordination polymers has resulted in fifteen new complexes with topologies that evolved along the periodic table and tunable photoluminescence properties.