X-ray scattering from the long spacing of completely crystalline oligoethylene glycol di-n-alkyl ethers

Autor:	Colin Booth, Roy L. Beddoes, Timothy G. E. Swales, Colin Price, R. C. Domszy
Rok vydání:	1985
Předmět:	chemistry.chemical_classification Materials science Scattering Plane (geometry) General Engineering X-ray law.invention Crystallography Temperature gradient Reflection (mathematics) Zigzag chemistry law Polymer chemistry Crystallization Alkyl
Zdroj:	Journal of Polymer Science: Polymer Physics Edition. 23:1585-1595
ISSN:	1542-9385 0098-1273
DOI:	10.1002/pol.1985.180230811
Popis:	Completely crystalline samples of oligoethylene glycol di-n-alkyl ethers, H(CH2)nO-(CH2CH2O)m(CH2)nH, where m is 9 or 15 and n is in the range 12-18, were orientated in capillaries by slow crystallization in a temperature gradient. X-ray scattering from the long spacings of the oriented samples, rotated continuously through 360°, was concentrated on the equator of a Debye–Scherrer photograph and many orders of reflection could be seen (e.g., up to order 30). The intensities of these reflections were analyzed by use of a model electron density distribution through the layer structure. Thus it was shown that the central oxyethylene block, in helical conformation, is oriented normal to the layer end plane, while the end alkyl bolcks, in planar zigzag conformation, are tilted relative to the layer end plane at an angle in the range 70°–64°.
Databáze:	OpenAIRE
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