Rotational viscosity in a nematic liquid crystal: A theoretical treatment and molecular dynamics simulation

Захаров, А. В.; Komolkin, Andrei V.; Maliniak, Arnold

doi:10.1103/physreve.59.6802

Cited by 48 publications

(32 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…None-the-less the two methods appear to give comparable results and a direct comparison with experiment for PCH5 (figure 11), points to this being a promising way of obtaining γ 1 . It is possible also to obtain γ 1 from calculations of rotational diffusion (RD) coefficient, as described by Zakharov and co-workers [103,104], and by forcing the nematic director to rotate under the influence of an external field [105]. These have been shown to give good agreement with experiment.…”

Section: Rotational Viscositymentioning

confidence: 88%

Progress in computer simulations of liquid crystals

Wilson

2005

International Reviews in Physical Chemistry

137

View full text Add to dashboard Cite

This article reviews some of the recent progress in the simulation of liquid crystals across a range of length and time scales. Simulators now have an extensive range of models at their disposal, ranging from fully atomistic studies where each atom is represented in a simulation, via hard or soft anisotropic potentials, to lattice models and director-based simulation methods. Each of these provide access to different phenomena. The progress towards accurate atomistic modelling of nematics is discussed in detail, pointing to improvements in force fields made recently and discussing the progress towards accurate prediction of material properties. Three material properties are discussed in detail: elastic constants, rotational viscosity and helical twisting powers. The simulation methods that can be employed to extract such properties are reviewed and the insights provided by recent results from atomistic and coarse-grained models are discussed. The article points also to the recent success of coarse-grained modelling in helping to understand the structure of complex macromolecular liquid crystals: liquid crystal polymers and liquid crystal dendrimers in which the macromolecules contain different types of interaction site. Finally, it is worth noting that throughout Nature liquid crystals occur as the archetypal self-assembled materials; able to form well-defined self-organized structures, which are often ordered at the nanoscale. With this in mind, some perspectives on the future use of these materials are presented, with suggestions for how liquid crystal simulation can be used to help in the design of the next generation of nanoscale devices.

show abstract

Section: Rotational Viscositymentioning

confidence: 88%

Progress in computer simulations of liquid crystals

Wilson

2005

International Reviews in Physical Chemistry

137

View full text Add to dashboard Cite

show abstract

“…all outputs are merely estimates and (iii) using MC it is also difficult to devise structural perturbations. [17][18][19] The latter types of simulation technique have advantages as: (i) it works as experimental bridge between structures and macroscopic kinetic data; (ii) it takes much longer time to get the simulation results; [4][5][6] (iii) it gives a route to dynamical properties of the system such as transport coefficients, time-dependent responses to perturbations, rheological properties and spectra, which is the obvious advantage of MD over MC. 20 The disadvantages of MD-techniques include (i) short time span; (ii) MD simulation design must be matched with the available computational power; (iii) during a MD simulation test, the most CPU intensive task is the evaluation of the potential, i.e.…”

Section: Computer Simulation In Liquid Crystals Researchmentioning

confidence: 99%

Investigating the Calculation of Rotational Viscosity of the Mixture Comprising Different Kinds of Liquid Crystals: Molecular Dynamics Computer Simulation Approach

et al. 2011

View full text Add to dashboard Cite

Molecular dynamics (MD) computer simulation techniques, as a powerful tool commonly utilized by the liquid crystal display (LCD) community, usually are employed for computing the equilibrium and transport properties of a classical many body system, since they are very similar to real experiments in many respects. In this paper we present molecular dynamics computer simulation results taken for a mixture of the two different kinds of nematic liquid crystals (LCs). We calculated rotational viscosity from Brownian behavior with friction of the mean director of the mixture comprising pentylcyanobiphenol (5CB) and decylcyanobiphenol (10CB) by using molecular dynamics computer simulation, where intermolecular potential parameter is Generalized AMBER force field (GAFF). Our computed results show a good agreement with the experimental results.

show abstract

“…Allen et al 11 have deduced analytical expressions for the rotational viscosity for hard convex bodies. For nematic liquid crystals composed of relatively large molecules with molecular weight in the order of 250 g / mol, Zakharov et al 12 and also Capar and Cebe 13 have studied the rotational viscosity as a function of temperature by using MD. To the best of our knowledge, no one has yet published any systematic study of the rotational viscosity as a function of density and temperature and for different molecular fluids.…”

Section: ͑2͒mentioning

confidence: 99%

Rotational viscosity of fluids composed of linear molecules: An equilibrium molecular dynamics study

Moore

Hansen

Todd

2008

The Journal of Chemical Physics

View full text Add to dashboard Cite

Non-Newtonian behavior and molecular structure of Cooee bitumen under shear flow: A non-equilibrium molecular dynamics study J. Chem. Phys. 142, 244501 (2015) In this paper, we investigate the rotational viscosity for a chlorine fluid and for a fluid composed of small linear molecules by using equilibrium molecular dynamics simulations. The rotational viscosity is calculated over a large range of state points. It is found that the rotational viscosity is almost independent of temperature in the range studied here but exhibits a power-law dependency on density. The rotational viscosity also shows a power-law relationship with the molecular length, and the ratio between the shear and rotational viscosities approaches 0.5 for the longest molecule studied here. By changing the number of atoms or united atomic units per molecule and by keeping the molecule length fixed, we show that fluids composed of molecules which have a rodlike shape have a lower rotational viscosity. We argue that this phenomenon is due to the reduction in intermolecular connectivity, which leads to larger fluctuations around the values possessed by the fluid on average. The conclusions here can be extended to fluids composed of uniaxial molecules of arbitrary length.

show abstract

Rotational viscosity in a nematic liquid crystal: A theoretical treatment and molecular dynamics simulation

Cited by 48 publications

References 38 publications

Progress in computer simulations of liquid crystals

Progress in computer simulations of liquid crystals

Investigating the Calculation of Rotational Viscosity of the Mixture Comprising Different Kinds of Liquid Crystals: Molecular Dynamics Computer Simulation Approach

Rotational viscosity of fluids composed of linear molecules: An equilibrium molecular dynamics study

Contact Info

Product

Resources

About