Effects of solute properties and concentrations on liquid crystals: N-(4-ethoxybenzylidene)-2,6-dideutero-4-n-butylaniline

Abstract

Articles you may be interested inEffect of lithium on the properties of a liquid crystal formed by sodium dodecylsulphate and decanol in aqueous solution J. Chem. Phys. 139, 014703 (2013); 10.1063/1.4811678 Obtaining the structure and bond rotational potential of a substituted ethane by NMR spectroscopy of solutions in nematic liquid-crystalline solvents Quantum-mechanical studies of NMR properties of solutes in liquid crystals: A new strategy to determine orientational order parameters Orientational and interaction induced dynamics in the isotropic phase of a liquid crystal: Polarization resolved ultrafast optical Kerr effect spectroscopyThe effects of the nature and concentration of the solutes 1,3,5-trichlorobenzene ͑TCB͒, benzene, chlorobenzene, o-dichlorobenzene, m-dichlorobenzene, and p-dichlorobenzene on orientational order in the nematic liquid crystal N-͑4-ethoxybenzylidene͒-2,6-dideutero-4-n-butylaniline are investigated using NMR spectroscopy. Seven separate samples containing differing concentrations of all solutes are investigated at constant temperature, at constant reduced temperature, at constant TCB orientational order, and at constant liquid crystal orientational order. Various schemes for comparison of orientational order among the samples are examined. For the experiments performed here, the most consistent method to compare solute orientational order in the different samples is to multiply results from the experiments performed at constant temperature by the factor needed to equate the TCB order parameters.

Nuclear magnetic resonance study of alkane conformational statistics

“…We note that in an earlier study on scaling among samples of differing concentrations it was found best to scale tcb order parameters and not potential parameters. 35 We also note in Figure 2 (bottom panels) that the Gβ ratios are also independent of temperature.…”

Testing Assumptions about Solute Concentration Dependence in Liquid Crystal NMR

“…One approach is to use solutes whose symmetry leads to two independent second-rank order parameters, and to compare ratios of these order parameters with theory . Unfortunately, these ratios are both concentration and temperature dependent, as can be demonstrated using the order parameters reported in ref . Thus, results for these solutes at finite concentrations also need to be extrapolated to zero concentration for meaningful comparisons to be made.…”

“…Alternatively, samples could be run at the same actual temperature, and some chosen solute order parameter (or liquid-crystal quadrupolar splitting) could be used to scale linearly order parameters among samples, or the scaling could be applied to the interaction energies of an assumed mean-field 16 interaction potential. These ideas were tested with experiments on a collection of aromatic solutes codissolved in the nematic liquid crystal N−(4-ethoxybenzylidene)-2,6-dideutero-4- n -butylaniline (EBBA) using seven different sample tubes, each with differing concentrations of solutes . In these experiments, it was found that the best comparison among samples was obtained from experiments run at the same actual temperature and using the order parameter of the solute 1,3,5-trichlorobenzene (tcb) as an orientational standard for scaling purposes.…”

Order and Conformation of Biphenyl in Cyanobiphenyl Liquid Crystals: A Combined Atomistic Molecular Dynamics and 1H NMR Study

“…[27] A further complication that arises upon studying a mixture is that, even though the pure components may be well described by the adopted FF, the mixed interactions may not be as satisfactorily described. [7,60,61] It then becomes important to estimate the nematic-isotropic transition temperature as accurately as possible in the simulations. Typically, this results in a partial disruption of the orientational order, which translates into a destabilisation of the nematic phase and a consequent shift of the nematicisotropic transition to lower temperatures.…”

“…[7] The most sensible way to compare measurements of orientational-order-dependent properties in different LC solvents and concentrations or, as in our case, to compare experimental results with simulations, is to refer to the same reduced temperature T r = T/T NI instead of the absolute temperature. [7,60,61] It then becomes important to estimate the nematic-isotropic transition temperature as accurately as possible in the simulations. To this end, once the approximate temperature range was identified, in which the nematic-isotropic transition occurs, we performed additional simulations in the narrow temperature range encompassing the phase transition.…”