SEM images of CPI hybrids containing (a) 0 (pure CPI), (b) 0.25, (c) 0.50, (d) 0.75, and (e) 1.00 wt% CS25A.

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A series of thermotropic liquid crystal copolyesters (Co-TLCPs) was prepared by melt polymerization using 2,5-diethoxyterephthalic acid (DTA), 2,7-dihydroxynaphthalene (DHN), and p-hydroxybenzoic acid (HBA) monomers, where the HBA content was varied (0–5 mol). At 3 mol HBA, the Co-TLCPs formed nematic mesophases, while below this concentration, the liquid crystalline phase did not appear. The Co-TLCP sample with 3 mol HBA was subjected to melt spinning and heat-treated under various conditions (temperature and time) to investigate their effect on the thermo–mechanical properties and degree of crystallinity. The objective was to determine the critical heat treatment condition that can maximize the properties of the spun Co-TLCP fibers. The microstructure of the heat-treated fiber was investigated using scanning electron microscopy, and the optimal annealing conditions were confirmed based on the morphology of the fiber, which exhibited a skin–core structure owing to the varying heat and pressure conditions applied during spinning.

[NH3(CH2)5NH3]MnCl4 crystals are grown via slow evaporation, and the crystal undergoes a phase transition at 298 K (TC) according to differential scanning calorimetry, and the structures determined via X-ray diffraction at 173 and 333 K are orthorhombic systems in the space group Imma. These results differed slightly from those previously reported, and the reasons for this are analyzed. The thermal stability is relatively high, with a thermal decomposition temperature of approximately 570 K. The 1H spin-lattice relaxation times t1ρ exhibited very large variations, as indicated by the large thermal displacement around the 1H atoms, suggesting energy transfer at ~TC, even if no structural changes occurred. The influences of the chemical shifts of 1H of NH3 and short t1ρ of C1 adjacent to NH3 in cation are insignificant, indicating a minor change in the N−H⋯Cl hydrogen bond related to the coordination geometry of the MnCl6 octahedron. These properties will be make it a potential application for eco-friendly solar cells.