A simple and fast method for evaluating the athermal limit of semirigid liquid polymers

A simple method is reported allowing the fast evaluation of the athermal limit that is implicitly present within the set of equations recently proposed by Jonah, Brostow and Hess, dealing with the anisotropic‐isotropic equilibria of single monodisperse or nearly monodisperse semirigid liquid polymers, including polymer liquid crystals. We have found an athermal limit dependent on the degree of rigidity θ of the given semirigid liquid polymer (θ being the fraction of its monomeric units belonging to rigid rodlike sequences within each semiflexible polymeric chain) and marked off by critical lengths η_al of the rigid sequences, giving rise to non‐finite asymptotic values of the anisotropic‐isotropic temperatures.     

Influence of processing method and components molecular structure on the phase behaviour of polyethylenes/dye blends

The phase dispersion of terthiophene alkyl derivatives on different polyethylene matrices was investigated. The PE affinity toward dichroic dyes with different structure, the effect of blending process and the influence of a polyolefinic compatibilizer on the homogeneity of host-guest blends were comparatively investigated by calorimetry, DSC and SEM analyses. For these purposes, polyethylenes with different molecular weights and densities and EVAc were used as host matrices. The polymeric compatibilizer was prepared by radical functionalization of a commercial low density polyethylene. The dichroic nature of the guest phase allowed to perform UV-Vis measurements in polarized light on oriented blend film samples. The dyes affinity toward PE is one of the key factor in obtaining oriented polyolefinic films with high optical performances for several applications.     

Amphiphilic Iminosugar Pharmacological Chaperones towards β-Glucocerebrosidase: Self-Assembly and Biological Activity

Pharmacological chaperones (PCs) can restore correct enzymatic activity at sub-inhibitory concentrations and are considered an emerging therapy for Gaucher Disease (GD). Amphiphilic PCs show more favourable cross-membrane properties and have a higher activity on cells than hydrophilic PCs. To investigate whether the biological activity of amphiphilic iminosugars is related to their state as monomers or as micellar aggregates, we synthesized some novel N-alkylated iminosugars and performed physico-chemical characterizations in the solid state and in aqueous dispersion of the best compound in terms of biological activity. The results suggest that the C12 N-alkylated iminosugar 10 exerts its biological activity in the monomeric state, and that the low cell viability observed in the presence of a 50 μM concentration of compound 10 is not related to the formation of micellar aggregates in solution.     

On the Origin of the Non-Arrhenius Na-ion Conductivity in Na3OBr

The sodium-rich antiperovskites (NaRAPs) with composition Na₃OB (B=Br, Cl, I, BH₄, etc.) are a family of materials that has recently attracted great interest for application as solid electrolytes in sodium metal batteries. Non-Arrhenius ionic conductivities have been reported for these materials, the origin of which is poorly understood. In this work, we combined temperature-resolved bulk and local characterisation methods to gain an insight into the origin of this unusual behaviour using Na₃OBr as a model system. We first excluded crystallographic disorder on the anion sites as the cause of the change in activation energy; then identified the presence of a poorly crystalline impurities, not detectable by XRD, and elucidated their effect on ionic conductivity. These findings improve understanding of the processing-structure-properties relationships pertaining to NaRAPs and highlight the need to determine these relationships in other materials systems, which will accelerate the development of high-performance solid electrolytes.