Brillouin scattering in the isotropic, nematic, and smectic-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>A</mml:mi></mml:math>phases of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi></mml:math>-cyanobenzylidene-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi></mml:math>-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>n</mml:mi></mml:math>-octyloxyla

Wergin, Alexander; Krasser, W.; Stiller, H.; Frischkorn, C. G. B.

doi:10.1103/physreva.20.1120

Cited by 16 publications

(4 citation statements)

References 20 publications

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“…The data for each temperature were Fourier analysed and by comparing the Fourier coefficients with the series expansion of the expression (2a), the elastic coefficients A, B and C were easily obtained. These values are contained in figure 2. The results are similar to those obtained previously [3][4][5][6][7]. In the smectic A phase both coefficients A and C extrapolate approximately linearly to zero as the smectic A-nematic transition is approached.…”

supporting

confidence: 91%

“…This gives in terms of the elastic tensor~ ~ -C33 0.01. Ultrasonic measurements in other systems [4][5][6][7] indicate considerably higher values for this difference.…”

mentioning

confidence: 84%

“…Such waves are predicted by the phenomenological elastohydrodynamic theory [1,2] and have been observed by Brillouin scattering in the smectic A and B phases of p-methylbutyl p[(p-methoxy-benzilidene) amino] cinnamate [3]. Ultrasonic and Brillouin scattering investigations in the smectic A and B phases [4][5][6][7][8] show the expected angular dependence of the velocity of longitudinal sound waves; shear waves, however have not been observed. We present here the results of Brillouin scattering in the smectic A and B phases of n-butyloxy-benzilidene n-octylaniline (in short BOBOA).…”

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confidence: 86%

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Brillouin scattering in SA and SB phases of butyloxy-benzilidene octylaniline

1981

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2014 Nous avons mesuré l'anisotropie des ondes sonores quasilongitudinales dans les phases SA et SB de n-butyloxy-benzilidène n-octylaniline. Les données expérimentales permettent de déterminer les grandeurs des trois constantes d'élasticité. Bien que la valeur de la constante d'élasticité correspondante aux ondes de cisaillement soit relativement très élevée, la propagation d'une telle onde n'a pas été observée. Abstract. 2014 The anisotropy of the quasilongitudinal sound waves in the SA and SB phases of n-butyloxy-benzilidene n-octylaniline was measured. From the data, three elastic constants were determined. A propagating shear wave was not observed in spite of a relatively large value of the relevant elastic constant.

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supporting

confidence: 91%

“…This gives in terms of the elastic tensor~ ~ -C33 0.01. Ultrasonic measurements in other systems [4][5][6][7] indicate considerably higher values for this difference.…”

mentioning

confidence: 84%

mentioning

confidence: 86%

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Brillouin scattering in SA and SB phases of butyloxy-benzilidene octylaniline

1981

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“…[ 28,29 ] The sound velocity in the nematic and smectic phases is anisotropic, but v L (α ≈ 0°)/ v L (α = 90°) is within 5% of unity at hypersonic frequencies. [ 30–32 ] The largest value of v L (α ≈ 0°)/ v L (α = 90°) that we found in the literature is 1.05 for 4′‐octyl‐4‐biphenylcarbonitrile (8CB) liquid crystals in the smectic phase. [ 33,34 ] This is much smaller than the values (e.g., 1.31 for the high T sub sample) for the itraconazole glasses presented in this work.…”

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confidence: 94%

Extreme Elasticity Anisotropy in Molecular Glasses

Cang

Wang

Bishop

et al. 2020

Adv Funct Materials

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Glasses are generally assumed to be isotropic and there are no literature reports of elastic anisotropy for molecular glasses. However, as glasses formed by physical vapor deposition can be structurally anisotropic, it is of interest to investigate the elastic anisotropy in these materials. Micro‐Brillouin light spectroscopy is used in several experimental geometries to determine the elastic stiffness tensors of three glass films of itraconazole vapor‐deposited at substrate temperatures (Tsub) of 330, 315, and 290 K, respectively. Significant elastic anisotropy is observed and, in these glasses, the elastic anisotropy shows a strong correlation with the molecular orientation. The out‐of‐plane and in‐plane Young's moduli of the high Tsub (330 K) sample, which features a predominantly vertical molecular orientation, exhibit a high anisotropy ratio of 2.2. The observed elastic anisotropy is much larger than those previously observed in liquid crystals and even many crystalline solids.

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