Structural characterization of Langmuir-Blodgett films of 2-dodecyl- and 2-pentadecyl-7,7,8,8-tetracyanoquinodimethane

Terashita, Shinichi; Nakatsu, Kazumi; Ozaki, Yukihiro; Mochida, Tadashi; Araki, Takao; Iriyama, Keiji

doi:10.1021/la00048a034

Cited by 21 publications

(28 citation statements)

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“…• 6 As another way in evaluating molecular orientation, Yarwood et al proposed the way of attenuated total reflection (A TR) spectra in combination with RA spectra. 7~9…”

Section: Introductionmentioning

confidence: 99%

Quantitative Analysis of Uniaxial Molecular Orientation in Langmuir-Blodgett Films by Infrared Reflection Spectroscopy

Hasegawa¹,

Takeda²,

Kawaguchi³

et al. 1995

Langmuir

143

202

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In analyzing optical properties of multilayered LB films with the uniaxial anisotropy around the surface normal, a new method for calculating infrared reflection-absorbances was developed, by extending Drude's anisotropic calculation theory for two-phase system to Hansen's optical theory for thin isotropic multilayers. With this method, infrared external reflection spectra of a 9-monolayer LB film of cadmium stearate prepared on a gallium arsenide substrate were analyzed to obtain molecular orientations. The result was in fair agreement with that obtained by X-ray diffractometry. Reflection-absorbance spectra of the same LB film on a silver-evaporated slide glass at various temperatures were also analyzed by the same method and the orientation angle of each molecular group was quantitatively obtained, clarifying the process of disordering with the increase of temperature. Further, the dependence of the degree of disordering on the monolayer location in LB films were discussed in light of the isotope substitution experiment.

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“…• 6 As another way in evaluating molecular orientation, Yarwood et al proposed the way of attenuated total reflection (A TR) spectra in combination with RA spectra. 7~9…”

Section: Introductionmentioning

confidence: 99%

Quantitative Analysis of Uniaxial Molecular Orientation in Langmuir-Blodgett Films by Infrared Reflection Spectroscopy

Hasegawa¹,

Takeda²,

Kawaguchi³

et al. 1995

Langmuir

143

202

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“…[9][10][11] Moreover, the fact that a weak shoulder of the a (CH 2 ) band was observed around 2927 cm Ϫ1 for the pure films also shows the similarity between the alkyl chain packing in these films and that of C 18 TCNQ films. [9][10][11] On the contrary, a (CH 2 ) and s (CH 2 ) bands were observed at 2921 and 2851 cm Ϫ1 with linewidths of 22 and 14 cm Ϫ1 , respectively, for the CT films. These observations indicate the alkyl chains in these films are rather loosely packed with non-negligible content of the gauche conformation.…”

Section: Molecular Orientation and Layered Structurementioning

confidence: 63%

“…[7][8][9][10][11] According to Chollet and Messier, 7 one can take into account the multiple reflection due to the thin films and estimate the out-of-plane orientation order parameter of the vibration mode under consideration, Sϭ͗3 cos 2 Ϫ1͘, where is the angle between the transition dipole moment and the normal axis of the film plane, as…”

Section: Methodsmentioning

confidence: 99%

Structural change of Langmuir and Langmuir–Blodgett films of alkylDCNQI induced by charge-transfer reaction at the air–water interface

Ikegami¹,

Lan

Nakamura

2000

The Journal of Chemical Physics

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UV-visible absorption spectrum of pure 2-methyl-5-octadecyl-N,N′-dicyanoquinonediimine (C18MeDCNQI) Langmuir films and that of C18MeDCNQI–CuI mixed Langmuir films indicated the occurrence of charge-transfer (CT) reactions at the air–water interface in the latter case. These Langmuir films were deposited onto solid substrates as Langmuir–Blodgett (LB) films by the horizontal lifting method. Polarized UV–visible–IR absorption spectra and x-ray diffraction patterns recorded for the obtained LB films revealed a drastic structural change induced by the CT reactions: An interdigitated bilayer structure was suggested for the pure films, while a monolayer structure for the CT films. Furthermore, the CT degree of the major component of the mixed LB films was estimated at −1, unlike in the case of Cu–DCNQI crystals, for which the CT degree is −2/3.

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“…A band due to a CH2 antisymmetric stretching mode of the alkyl chain is identified near 2920 as a doublet; this was thought to arise from the crystal field splitting. 21 During the heating, the relative intensities of the doublet bands change near 40˚C and the band becomes a single one above 60˚C. The CH2 symmetric stretching band at 2850 cm -1 gives abrupt upward shift to 2853, 2855, and 2856 cm -1 at 40, 60, and 102˚C, respectively; such shifts are indicative of increases in conformational disorder.…”

Section: Discussionmentioning

confidence: 97%

Phase-Transitions in Langmuir-Blodgett and Cast Films of a Ferroelectric Liquid Crystal

Wen

Jiang

et al. 2007

ANAL. SCI.

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Langmuir-Blodgett films and cast films of a ferroelectric liquid crystal of sec-butyl-6-(4-(nonyloxy)benzoyloxy)-2-naphthoate have been fabricated. Their thermal behavior was investigated using infrared spectroscopy at elevated temperature combined with principal component analysis. The result shows a new phase transition from smectic A to nematic phase, compared to the phase sequence obtained by polarizing optical microscopy. Another solid transition of different isomeric crystals was also found, which was confirmed by calorimetric measurement.

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Structural characterization of Langmuir-Blodgett films of 2-dodecyl- and 2-pentadecyl-7,7,8,8-tetracyanoquinodimethane

Cited by 21 publications

References 0 publications

Quantitative Analysis of Uniaxial Molecular Orientation in Langmuir-Blodgett Films by Infrared Reflection Spectroscopy

Quantitative Analysis of Uniaxial Molecular Orientation in Langmuir-Blodgett Films by Infrared Reflection Spectroscopy

Structural change of Langmuir and Langmuir–Blodgett films of alkylDCNQI induced by charge-transfer reaction at the air–water interface

Phase-Transitions in Langmuir-Blodgett and Cast Films of a Ferroelectric Liquid Crystal

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