Materials 2014, 7(3), 1502-1519; doi:10.3390/ma7031502
Article

Dispersion of γ-Alumina Nano-Sized Spherical Particles in a Calamitic Liquid Crystal. Study and Optimization of the Confinement Effects

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Received: 16 January 2014; in revised form: 5 February 2014 / Accepted: 12 February 2014 / Published: 27 February 2014
(This article belongs to the Special Issue Liquid Crystals)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: We report an experimental study on confined systems formed by butyloxybenzylidene octylaniline liquid crystal (4O.8) + γ-alumina nanoparticles. The effects of the confinement in the thermal and dielectric properties of the liquid crystal under different densities of nanoparticles is analyzed by means of high resolution Modulated Differential Scanning Calorimetry (MDSC) and broadband dielectric spectroscopy. First, a drastic depression of the N-I and SmA-N transition temperatures is observed with confinement, the more concentration of nanoparticles the deeper this depression is, driving the nematic range closer to the room temperature. An interesting experimental law is found for both transition temperatures. Second, the change in shape of the heat capacity peaks is quantified by means of the full width half maximum (FWHM). Third, the confinement does not noticeably affect the molecular dynamics. Finally, the combination of nanoparticles and the external applied electric field tends to favor the alignment of the molecules in metallic cells. All these results indicate that the confinement of liquid crystals by means of γ-alumina nanoparticles could be optimum for liquid crystal-based electrooptic devices.
Keywords: liquid crystals; MDSC calorimetry; dielectric spectroscopy; polydispersive nanoparticles; confinement; γ-alumina
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MDPI and ACS Style

Diez-Berart, S.; López, D.O.; Sebastián, N.; de la Fuente, M.R.; Salud, J.; Robles-Hernández, B.; Pérez-Jubindo, M.Á. Dispersion of γ-Alumina Nano-Sized Spherical Particles in a Calamitic Liquid Crystal. Study and Optimization of the Confinement Effects. Materials 2014, 7, 1502-1519.

AMA Style

Diez-Berart S, López DO, Sebastián N, de la Fuente MR, Salud J, Robles-Hernández B, Pérez-Jubindo MÁ. Dispersion of γ-Alumina Nano-Sized Spherical Particles in a Calamitic Liquid Crystal. Study and Optimization of the Confinement Effects. Materials. 2014; 7(3):1502-1519.

Chicago/Turabian Style

Diez-Berart, Sergio; López, David O.; Sebastián, Nerea; de la Fuente, María R.; Salud, Josep; Robles-Hernández, Beatriz; Pérez-Jubindo, Miguel Ángel. 2014. "Dispersion of γ-Alumina Nano-Sized Spherical Particles in a Calamitic Liquid Crystal. Study and Optimization of the Confinement Effects." Materials 7, no. 3: 1502-1519.

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