Two types of rare earth–organic frameworks constructed by racemic tartaric acid

Hydrothermal reactions of rare earth oxides with racemic tartaric acid (H₂tar) yielded 7 rare earth(III) MOFs with general formulas [R₂(tar)₃(H₂O)₂]_n (R=Y (1), Sm (4), Eu (5), Tb (6), Dy (7)) and [R₂(tar)₂(C₂O₄)(H₂O)₂]_n·4nH₂O (R=La (2), Nd (3)). X-ray powder diffraction analysis and single-crystal X-ray diffraction analysis reveal that they present two different structural types. MOFs 1, 4, 5, 6 and 7 are isostructural and crystallize in the orthorhombic non-centrosymmetric space group Iba2, and feature unusual fsc-3,4-Iba2 topology. MOFs 2 and 3 are isostructural and crystallize in monoclinic P2₁/c space group and display rare fsx-4,5-P2₁/c topology containing hydrophilic channels bounded by triple helical chains along a axis. MOFs 3, 4, 5, 6 and 7 exhibit intense lanthanide characteristic photoluminescence at room temperature.     

Novel redox-active ionic thermotropic liquid crystalline complexes of polyelectrolyte and ferrocenyl surfactants

Redox-active polyelectrolyte-surfactant complexes(PSC) were prepared via the ionic self-assembly of sodium poly(styrenesulfonate) (PSS) and ferrocenyl surfactant,(11-ferrocenylundecyl)trimethylammonium bromide(FTMA) in aqueous solution. The PSS-FTMA complex exhibited an ordered interdigitated monolayer mesomorphous structure with the long period of d = 3.13 nm,and was in the ionic thermotropic liquid crystal SmA state at room temperature.Interestingly,in the solid complex, the ferrocenyl moieties formed H-aggregation showing an increase in theπ-π~* energy transfer of cyclopentadienes in the ferrocene moieties as known from the blue-shift in the UV spectrum.The complexes showed higher thermal stability compared with their components due to the ionic interaction.The PSS-FTMA film had a good redox reversibility,which promised to be used in electrochemical sensors.     

Synthesis and thermal energy storage properties of the polyurethane solid–solid phase change materials with a novel tetrahydroxy compound

Based on the phase change theory, a novel tetrahydroxy compound (THCD) was designed and prepared. Depending on the spatial structure of the tetrahydroxy compound, a form-stable thermoplastic polyurethane solid–solid phase change material (TPUPCM) was synthesized via employing PEG as soft segments, while multi-benzene ring structure made by 4,4′-diphenylmethane diisocyanate and tetrahydroxy compound as hard segments. The composition and structure of THCD and TPUPCM, the TPUPCM’s the weight average molecular weight and number average molecular weight, dissolving and melting abilities, phase change behaviors, thermal performances and crystalline morphology were investigated by Fourier transform infrared spectrometer, ¹H nuclear magnetic resonance spectrometer, multiangle laser light scattering apparatus, differential scanning calorimentry, dynamic mechanical thermal analysis, thermogravimetry analysis system, wide-angle X-ray diffraction, polarizing optical microscopy. The results show that the solid–solid phase change material owns excellent phase change properties and a broad processing temperature range. The heating cycle phase change enthalpy is 137.4 J/g, and the cooling cycle phase change enthalpy is 127.6 J/g. The started decomposition temperature and the maximum decomposition temperature are at 323.5 and 396.2 °C, respectively. Furthermore, the solid–solid phase change material is dissolvable, meltable and can be processed directly, and has great potential applications in thermal energy storage.     

Shear Stress and Dielectric Analysis of H3PO4 Doped Polyaniline Based Electrorheological Fluid

We synthesized phosphoric acid (PA) doped polyaniline (PANI) particles (PANI‐PA) and investigated their electrorheological (ER) and dielectric characteristics when they were dispersed in silicone oil. Flow curves of the PANI‐PA based ER fluid under several applied electric field strengths were analyzed using a shear stress model. We also examined ER characteristics based on the relaxation time obtained from the dielectric spectrum.