Materials Science Forum Vol. 807

Abstract: Nanocomposite solid polymer electrolytes comprise of PMMA (poly methyl methacrylate), PVP (poly vinyl pyrolidone), MSA (methanesulfonic acid) and TiO₂ as nanofiller were prepared by solution casting technique at different compositions. Sample with 1 mol% incorporated TiO₂ has shown maximum conductivity and its value was found as 2.82 ×10^-5 S/cm. The value of conductivity has been enhanced to about 31% upon the addition of nanofiller. The relaxation time for all the prepared composites as well as for the composite having maximum conductivity at various isotherms have been calculated from the loss tangent plot. The frequency and temperature dependence of dielectric constant and dielectric loss nanocomposite solid polymer electrolytes have also been studied. The modulus analysis confirms the non-Debye type formalism in the prepared composites.

Abstract: Nanofluids are colloidal suspensions of nanoparticles in a base fluid which are mainly used as modern heat transfer fluids. The applications of nanofluids include electronic cooling systems, direct absorption solar collectors, magnetic smart fluids and in biomedical treatments. The success of these applications depends on stability of nanofluid. In the present work TiO₂ nanofluids have been synthesized by two step technique .The nanoparticle of TiO₂ are prepared by sol gel and characterized by XRD, SEM and UV. The sedimentation of prepared nanofluid is observed by the gravity sedimentation method and transmitted intensity is recorded by a photo detector. A profile between the transmitted intensity and distance of nanofluid from laser source is obtained which shows the potential application of nanofluid as optical sensors for detecting stability of nanofluid.

Abstract: In this work, synthesis of ZnO nanoparticle by solution method and its application in non-volatile memory is reported. Nanocrystalline ZnO particles were prepared by a novel chemical route using the combination of zinc nitrate [Zn (NO₃)₂ 6H₂O] and sodium hydroxide [NaOH] at low temperature. The effects of temperature and bath concentration for the synthesis of ZnO powder have been studied. Synthesized powder was characterized by X-ray diffraction (XRD), UV-Vis spectrometer, transmission electron microscopy (TEM) and photoluminescence. Using the prepared ZnO nanoparticles with organic PMMA; non-volatile memory cells were prepared and studied its switching property.

Abstract: The amino functionalized magnesium phyllosilicate clay (AC) intercalated over PVA-Nafion hybrid nanocomposite membranes were prepared by sol-gel method. The free standing membranes were obtained by solution recasting. The composition of clay materials such as AC and montmorillonite (MMT) was varied between 2-10 wt.% with respect to PVA-Nafion content. The molecular interactions and surface morphology of nanocomposite membranes were investigated by FT-IR and SEM analyses respectively. The thermal and mechanical stabilities of nanocomposite membranes were studied using TGA and Nanoindentation techniques. For 6 wt. % AC/PVA-Nafion, TGA results showed no appreciable mass change up to 380 °C and hardness calculated from nanoindentation studies was nearly 30 % higher than the other compositions. An improved conductivity was obtained for 6 wt. % AC/PVA-Nafion (1.4×10^-2 S/cm) compared to pure Nafion (1.2×10^-2 S/cm) and PVA-Nafion and MMT/PVA-Nafion composite membranes. From these studies, we observed that 6 wt. % AC/PVA-Nafion membrane possessed a good conductivity with higher thermal and mechanical stabilities.

Abstract: 2, 6-Diaminoanthraquinone is used in drug delivery. The absorption and fluorescence spectral properties of 2,6-Diaminoanthraquinone (DAAQ) have been investigated in a series of organic solvents with different polarity functions ranging from 0.207 to 0.762.The different solvents used are Tetrahydrofuran (THF) (0.207), Dimethylformamide (DMF) (0.404), ethanol (0.654) and Methonal (0.762).The fluorescence shifts are more pronounced than the absorption shifts indicating that the change in dipole moment is positive. The change in dipole moment and the ratio of the dipole moments are determined and discussed by Solvatochromism method. The third order nonlinearity of 2,6-DAAQ in PVA dissolved in DMF solution is determined using Electroabsorption. Higher order nonlinearities can be deduced on successful recording of the stark spectrum at the higher order of the applied electric field.