Etude par spectroscopie EXAFS au seuil K du cuivre des phases cristalline et colomnaire du stéarate de cuivre

Abied, H.; Guillon, Daniel; Skoulios, A.; De×pert, H.; Giroud‐Godquin, Anne‐Marie; Marchon, Jean‐Claude

doi:10.1051/jphys:01988004902034500

Cited by 48 publications

(22 citation statements)

References 16 publications

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“…This independence was interpreted as an indication of a compact and regular packing of the polar heads within the columnar cores, in close connection with the coordination geometry of each metal atom considered [9]. In the particular case of copper (II) soaps, this was recently confirmed by EXAFS spectroscopy [16]. To investigate the thermal behavior of the stacking period in the columnar phase of PDHS, a series of small-angle X-ray diffraction patterns were recorded automatically as a function of temperature.…”

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confidence: 72%

Liquid crystalline nature of poly(di-n-hexylsilane)

et al. 1989

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Résumé. 2014 Dans ce travail, on étudie par diffraction des rayons X et microscopie optique en lumière polarisée la structure en fonction de la température d'un poly(di-n-hexylsilane). Au Abstract. 2014 Polarizing optical microscopy and X-ray diffraction were used to study the structure of poly(di-n-hexylsilane) as a function of temperature. Liquid crystalline in nature, the polymer above 42 °C shows hexagonal columnar symmetry, with the columns formed of single polymer chains. The stacking period of the dihexylsilicon repeat units along the columnar axis is of about 1.56 Å. Far from being all-trans as in the low-temperature crystal, the backbone conformation in the high-temperature mesophase is presumably close to an all-gauche helical conformation. J. Phys. France 50 (1989) Introduction.

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confidence: 72%

Liquid crystalline nature of poly(di-n-hexylsilane)

et al. 1989

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“…This fact was seen earlier in a DSCpolarizing optical microscopy-PXRD study on some even members from 12 < nC < 22 31 and proved by extended X-ray absorption fine structure (EXAFS) on members with nC = 6, 12, 18, 22, 50 and copper(II) stearate. 51 So, the local structure at short distances is similar for the crystal and for the liquid crystal phases, the difference being the long-range order (above 6−8 Å) lost in the latter, which is obvious for the fluid nature of the mesophase.…”

Section: Crystal Growth and Designmentioning

confidence: 95%

Study of the Polymorphism in Copper(II) Decanoate through Its Phase Diagram with Decanoic Acid, and Texture of the Columnar Thermotropic Liquid Crystal Developable Domains in This and Similar Systems

Riesco¹,

Martínez-Casado

Cheda³

et al. 2014

Crystal Growth & Design

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A new third polymorph of copper(II) decanoate has been found by two methods: from the crystallization of the salt− acid solution and from a specific thermal treatment of the polymorph obtained in n-heptane. The new polymorph, whose crystal structure has been solved for the first time, is the most stable from the thermodynamic point of view. It presents a bilayer structure, but with two different types of paddle-wheels catenae with opposite orientations. This polymorphism as well as the temperature vs composition phase diagram of the system, [(1 − x) C 9 H 21 CO 2 H + (x) (C 9 H 21 CO 2 ) 2 Cu], were solved by differential scanning calorimetry, Fourier transform infrared spectroscopy, Xray diffraction, pair distribution function, and optical microscopy. The singularities of the phase diagram are (a) a Krafft-like process of molecular association of the copper(II) decanoate into the acid solution, at about T = 361.5 K and x = 0.022 (forming salt-acid adducts of 1:1 stoichiometry); (b) a fusion transition as an invariant (T = 379.1 K) of the solid salt in excess from the copper(II) decanoate crystal phase to the discotic liquid crystal, forming homeotropic developable domains (seen for the first time in these systems) of the pure salt into the saturated acid solution. These domains are seen not only in the copper(II) decanoate but also in other members of the series, at high salt concentration in the corresponding acid solution, and allow identification of the hexagonal columnar discotic structure of the mesophase (with the exception of the copper(II) butanoate, where the tetragonal domains with tilted disks, paddle-wheels, were seen in the same salt−acid region).

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“…The small upturn at very low T is usually due to paramagnetic impurities. Abied et al have shown that the molecular piling occurs through one copper atom interacting with the oxygen atom of its neighbour [16]. No intermolecular Cu-Cu interactions are therefore involved in the bulk state.…”

Section: Encapsulating Self-assembled Filaments In Polymer Fibrilsmentioning

confidence: 99%

Hybrid Physical Gels from Polymers and Self-Assembled Systems: A Novel Path for Making Functional Materials

Guenet

2018

Preprint

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Etude par spectroscopie EXAFS au seuil K du cuivre des phases cristalline et colomnaire du stéarate de cuivre

Cited by 48 publications

References 16 publications

Liquid crystalline nature of poly(di-n-hexylsilane)

Liquid crystalline nature of poly(di-n-hexylsilane)

Study of the Polymorphism in Copper(II) Decanoate through Its Phase Diagram with Decanoic Acid, and Texture of the Columnar Thermotropic Liquid Crystal Developable Domains in This and Similar Systems

Hybrid Physical Gels from Polymers and Self-Assembled Systems: A Novel Path for Making Functional Materials

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