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ABSTRACT In this article, bioplastic polyethylene furanoate (PEF) is synthesized using polycondensation of 2,5‐furandicarboxylic acid and ethylene glycol at a temperature of 220°C using a solid nanowire based super‐acid catalyst. The super acid catalyst is made by phosphating titania nanowires. Specifically, the reactions resulted in over 90% FDCA conversion and 85% PEF yield in a short period of 3 h using superacid catalysts at a loading of < 1% by wt. The mechanical properties of PEF, including glass transition temperature (84°C), melting point (210°C), and crystallinity (1.48 g/cm ³ ), demonstrate the high quality of the PEF produced. Barocaloric properties of resulting PEF polymers are also studied which show promise.

The polarization-resolved Raman spectra of two-dimensional Cr₂Se₃ synthesized via chemical vapor deposition (CVD) and chemical vapor transport (CVT) techniques were investigated in detail. The samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). A distinct polarization dependence was observed in the Raman intensity of all the Cr-Cr, Cr-Se, and Se-Se modes in both samples. The observed angle-dependent Raman intensities of each peak could be related to the crystal structure-specific Raman tensor. XRD results of the bulk Cr₂Se₃ sample synthesized via CVT confirm its trigonal crystal structure, and the Raman peaks can be fitted using the Raman tensors for the A_g and E_g modes for both the parallel and crossed polarizations. However, for the Cr₂Se₃ samples directly grown on Si/SiO₂ substrates by CVD, it was necessary to assume the triclinic crystal structure in order to explain the polarized Raman dependence of all the peaks in both parallel and crossed polarization directions. Furthermore, this is the first experimental result suggesting the existence of triclinic Cr₂Se₃ crystal structure, which has been theoretically predicted in the Materials Project database.