Doping a Mixture of Two Smectogenic Liquid Crystals with Barium Titanate Nanoparticles

Lorenz, Alexander; Zimmermann, Natalie; Kumar, Satyendra; Evans, Dean R.; Cook, Gary; Martínez, Manuel Fernández; Kitzerow, Heinz‐S.

doi:10.1021/jp310624c

Cited by 21 publications

(7 citation statements)

References 37 publications

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“…Experimental details of measurements performed at beamline ID02 of the European Synchrotron Radiation Facility (ESRF) are described in Refs. [23,24]. During these measurements, the sample temperature was changed continuously but slowly (1.0°C/min).…”

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confidence: 99%

Columnar molecular aggregation in the aqueous solutions of disodium cromoglycate

et al. 2014

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Stack, chimneylike, and threadlike assemblies have previously been proposed for the structure of disodium cromoglycate (DSCG) aggregates in aqueous solutions. The results of the synchrotron x-ray scattering investigations reported here reveal the formation of simple columnar assemblies with π-π stacking at a separation of 3.4 Å between the DSCG molecules. Lateral separation between the assemblies is concentration and temperature dependent, varying from ∼35 to 42 Å in the orientationally ordered nematic (N) phase and from 27 to 32 Å in the columnar or middle (M) phase having long range lateral positional order. The assemblies' length depends on concentration and consists of ∼23 molecules in the N phase, becoming three to ten times larger in the M phase. The scission energy is concentration dependent in the N phase with values ∼7.19 ± 0.14 k_{B}T (15 wt %), 2.73 ± 0.4 k_{B}T (20 wt %), and 3.05 ± 0.2 k_{B}T (25 wt %). Solutions of all concentrations undergo a spinodal decomposition at temperatures above ∼40 °C, resulting in DSCG-rich regions with the M phase and water-rich regions in the N and isotropic phases.

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confidence: 99%

Columnar molecular aggregation in the aqueous solutions of disodium cromoglycate

et al. 2014

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“…Their width for doped 5CB is much larger than that in doped 8CB (inset). The smectic peak at ≈1.9 nm −1 is seen in scattering curves of doped 8CB at 30 • C. The calculated d ≈ 3.3 (±0.025) nm corresponds to smectic layer spacing of the stable SmA d phase of the neat 8CB [14,29]…”

Section: Resultsmentioning

confidence: 87%

“…From these dispersions, stressed BaTiO 3 nanoparticles, which possess permanent electric polarization, can be harvested [13]. Generally, doping of LCs with milled BaTiO 3 nanoparticles allows one to vary the structural properties of smectic LCs [14] and to enhance the performance of devices based on both the nematic LCs [15][16][17][18][19][20] and ferroelectric LCs [21].…”

Section: Introductionmentioning

confidence: 99%

Bilayers in nanoparticle-doped polar mesogens

et al. 2013

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Structures of the mesophases of five members of the 4-n-alkyl-4'-cyanobiphenyl homologous series (4-n-butyl-4'-cyanobiphenyl to 4-n-octyl-4'-cyanobiphenyl) doped with milled BaTiO_{3} nanoparticles were investigated by x-ray scattering. Clear solutions of each of the 4-n-alkyl-4'-cyanobiphenyls were first prepared in n-heptane and then doped with an n-heptane/nanoparticle dispersion, which led to gelation. The nanogels were found to be one-dimensional, multilayered, smectic nanostructures in each case. Surprisingly, a characteristic layer spacing of 4.5 nm was observed in all five homologues. Synchrotron x-ray scattering study of the multilayer structures of doped 4-n-pentyl-4'-cyanobiphenyl and 4-n-octyl-4'-cyanobiphenyl revealed nine orders of the primary Bragg reflection which were used to calculate the electron density profiles of the multilayers by Fourier analysis. The multilayers were found to consist of molecular bilayers wherein the mesogens were arranged in a head-to-head assembly of the polar head groups. The alkyl tails of the mesogenic molecules were freely movable and the tail-to-tail assembly was stabilized by heptane. The dissolved nanoparticles clearly induced a new self-assembled nanostructure in which the rigid aromatic part, and not the overall length, of the molecules defined the layer spacing.

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“…8,15 Recently, the harvesting technique proposed by G. Cook et al has been used for extracting single nanoparticles with strong permanent dipole moments. [16][17][18][19][20][21][22] As reported by A. Rudzki et al, harvested ferroelectric barium titanate (BaTiO 3 ) nanoparticles present a polarization four times higher than that of the non-harvested nanoparticles. 21,22 In this paper, we use broadband dielectric spectroscopy to determine the dielectric properties and phase transitions of the 4-n-octyl-4 0 -cyanobiphenyl liquid crystal (8CB) doped with harvested and nonharvested ferroelectric nanoparticles.…”

Section: Introductionmentioning

confidence: 83%

A comparative study of nematic liquid crystals doped with harvested and non-harvested ferroelectric nanoparticles: phase transitions and dielectric properties

et al. 2017

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Doping a Mixture of Two Smectogenic Liquid Crystals with Barium Titanate Nanoparticles

Cited by 21 publications

References 37 publications

Columnar molecular aggregation in the aqueous solutions of disodium cromoglycate

Columnar molecular aggregation in the aqueous solutions of disodium cromoglycate

Bilayers in nanoparticle-doped polar mesogens

A comparative study of nematic liquid crystals doped with harvested and non-harvested ferroelectric nanoparticles: phase transitions and dielectric properties

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