http://hdl.handle.net/2289/149 Search the Channel search http://dspace.rri.res.in:8080/jspui/simple-search http://hdl.handle.net/2289/5590 Title: Synthesis and characterisation of novel alkoxycyanobiphenyl-substituted rufigallols<br/><br/>Authors: Pal, Santanu Kumar; Kumar, Sandeep<br/><br/>Abstract: Microwave-assisted synthesis of novel alkoxycyanobiphenyl-substituted rufigallols are reported by systematically replacing one, two, four, five or six cyanobiphenyl-tethered alkoxy chains. The synthesis of the target compounds was challenging since classical reactions failed to produce these hybrids. Chemical structures of the hybrids were determined by 1H nuclear magnetic resonance (NMR), 13C NMR, infrared, ultraviolet spectroscopy and elemental analysis. The thermotropic liquid crystalline properties of the new compounds were investigated by polarising optical microscopy, differential scanning calorimetry and X-ray diffractometry<br/><br/>Description: Restricted Access. http://hdl.handle.net/2289/5589 Title: Enhanced stability of the columnar matrix in a discotic liquid crystal by insertion of ZnO nanoparticles<br/><br/>Authors: Supreet; Kumar, Sandeep; Raina, k k; Pratibha, R.<br/><br/>Abstract: An experimental characterisation of dispersions of ZnO nanoparticles (NPs) in the columnar matrix of a discotic liquid crystal has been carried out. Thermophysical properties have been investigated by absorbance spectroscopy, differential scanning calorimetry, polarising optical microscopy, dielectric measurements, dc conductivity, X-ray diffraction and infrared (IR) dichroism technique. The experimental results show that inclusion of ZnO NPs into the columnar matrix enhances the orientational order in the columnar phase and does not affect the two-dimensional hexagonal lattice. The alignment in homeotropic samples is also found to be better with the addition of the NPs. The real (ϵ′) and imaginary parts (ϵ′′) of the permittivity increase by a small amount in the dispersions. The order parameter measured using the IR dichroism technique in the face-on geometry (homeotropic alignment) shows an enhancement for the composite system. The dc conductivity is also found to increase by an order of magnitude by addition of the NPs. These results suggest an improved stacking of the disc-like molecules within the columns by the insertion of the ZnO NPs possessing high charge mobility. Such composite systems would be highly beneficial for potential applications such as organic conductors.<br/><br/>Description: Restricted Access. http://hdl.handle.net/2289/5587 Title: Assembly and organization of structurally novel amphiphilic molecules at air-water and air-solid interfaces<br/><br/>Authors: Kumar, Bharat<br/><br/>Description: Restricted Access http://hdl.handle.net/2289/5575 Title: Synthesis and Liquid crystal property of new fluoro coumarin carboxylates<br/><br/>Authors: Mahadevana, Kittappa M; Harishkumara, Hosanagara N; Masagalli, Jagadeesh N; Srinivasa, H.T.<br/><br/>Abstract: New liquid crystalline 4-alkoxyphenyl-coumarin-3-carboxylates 6a–e, 7a–g, 8a–e, and 9a–e were prepared by reacting various coumarin-3-carboxylic acids 5a–d with 4-(alkoxy) phenols 4a–g in the presence of 1(3-dimethylaminopropyl-3-ethylcarbodiimide/dimethyl amino pyridine (EDCI/DMAP) as a coupling agent. The structures of the new coumarin derivatives were confirmed by spectral analysis and the liquid crystalline property was established by polarizing optical microscope and by differential scanning calorimetric techniques. The diethyl amine and morpholine were taken as electron-donating and –CF3 as electron-withdrawing groups at the seventh position of the coumarin-3-carboxylic acids to check the mesomorphic property in all new 4-alkoxyphenyl-coumarin-3-carboxylates. Among them, only 4-alkoxyphenyl-7-triflouromethyl-coumarin-3-carboxylates 7a–g exhibited liquid crystalline SmA phase<br/><br/>Description: Restricted Access.