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We used CaCl 2 and NH 4 F from Merck Company for synthesis CaF 2 NPs. We synthesized CaF 2 Nanoparticales (NPs) using Co-precipitation and hydrothermal method successfully. The synthesized NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), UV-Vis spectroscopy and Photoluminescence (PL) techniques. The XRD results indicated the formation of CaF 2 NPs with Cubic phase and the crystallite size is estimated using Scherrer's formula to be in the range 20-27nm for the powders prepared by co-precipitation and 20-31nm for hydrothermal methods, respectively. TEM images revealed the grains have almost spherical shape. Optical absorption spectrum shows a strong absorption edge at about 300nm.

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This paper reports electromagnetic interference (EMI) shielding effectiveness (SE) and UV-shielding performance of polyvinylpyrrolidone (PVP)-TiO 2 /polyacrylonitrile (PAN)-SiO 2 nanofibre nanocomposites synthesized via the single nozzle co-electrospinning method. Herein, three samples with different average diameters were fabricated using 0.3, 0.4 and 0.5 ml h −1 flow rates during the electrospinning process. Morphological characterization confirmed that a core-shell structure of nanofibre nanocomposites was formed successfully. The EMI SE of the as-prepared nanofibre nanocomposites was studied using a vector network analyser over the full X-band (8-12 GHz) frequency at room temperature. The experimental results demonstrate excellent microwave absorption properties for all samples. PVP-TiO 2 /PAN-SiO 2 nanofibres with 596.67 nm average diameter show maximum total EMI (110 dB at about 9 GHz) and 98% UV-shielding performance.