In this work, we report on the preparation of sodium dodecyl sulfate (SDS) surfactant added cobalt ferrite (CoFe 2 O 4 ) magnetic nanoparticles by a co-precipitation method at various concentrations (0.04, 0.08, 0.12, 0.16 and 0.20 M) of SDS. The formation of a single phase cubic spinel structure is confirmed by XRD analysis. FTIR study confirms the presence of Fe-O symmetrical stretching vibrations in the tetrahedral site. TEM images imply that the SDS surfactant significantly limits the agglomeration of CoFe 2 O 4 nanoparticles. A dielectric study reveals that the SDS added CoFe 2 O 4 has a higher dielectric constant than that of pure CoFe 2 O 4 nanoparticles. Magnetic measurements showed the enhanced saturation magnetization (138.75 emu g À1 ), coercivity (775.69 Oe) and retentivity (60.23 emu g À1 ) for 0.08 M SDS added CoFe 2 O 4 nanoparticles. Further, the results obtained in the present study suggest that the surfactant can significantly modify the size and morphology of the prepared CoFe 2 O 4 nanoparticles.

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This work deals with the incorporation of propylene carbonate (PC) as a plasticizer in conjunction with poly (ethylene oxide) (PEO), silver triflate (AgCF 3 SO 3) and nanocrystalline tin oxide (SnO 2) for obtaining the nanocomposite polymer electrolyte system (PEO) 50 AgCF 3-SO 3 :2 wt% SnO 2 ? x wt% PC (x = 10, 20, 30 and 40) by solution casting method. The present electrical conductivity data extracted by means of complex impedance spectroscopic analysis in the frequency range 20 Hz-1 MHz and over the temperature domain 298-373 K have demonstrated that the maximum electrical conductivity value of 5.9 9 10-5 S cm-1 at 298 K would be possessed by the specimen containing 30 wt% PC incorporated into the optimized nanocomposite system (PEO) 50 AgCF 3 SO 3 :2 wt% SnO 2. Silver ionic transference number (t Ag?) data evaluated using AC/DC polarization technique have indicated that the highest t Ag? value of 0.52 could be realized in the case of the specimen (PEO) 50 AgCF 3 SO 3 :2 wt% SnO 2 ? 30 wt% PC, whereas the complexation of the plasticizer within the nanocomposite electrolyte has been deduced from the detailed Fourier transform infrared spectroscopic investigation owing to the fact that such results have revealed the appearance of absorption bands corresponding to free triflate ions (CF 3 SO 3-) and PC. Surface morphological features of pure PEO and (PEO) 50 AgCF 3 SO 3 :2 wt% SnO 2 ? 30 wt% PC nanocomposite systems were analysed through scanning electron microscope. The feasibility of a reduction in the degree of crystallinity of the plasticized system has been indicated by the X-ray diffraction data and confirmed from differential scanning calorimetric results obtained in terms of quantification of crystallinity and reduction in the glass transition temperature due to the addition of the chosen plasticizer into the nanocomposite polymer electrolyte matrix. Interestingly, the all solid-state cell based on the nanocomposite polymer electrolyte, namely, (PEO) 50 AgCF 3 SO 3 :2 wt% SnO 2 ? 30 wt% PC and silver anode has exhibited an open circuit voltage of 676 mV and short circuit current of 192 lA at room temperature.

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