Defect orientation on the chain folded surfaces of two-arm poly(ethylene oxide) lamellar crystals

Autor:	Ian Mann, Gi Xue, Song-Wook Lee, Bon-Suk Moon, Er-Qiang Chen, Frank W. Harris, Stephen Z. D. Cheng, Shi Jin
Rok vydání:	1999
Předmět:	Polymers and Plastics Ethylene oxide Stereochemistry Organic Chemistry Oxide Crystal symbols.namesake Crystallography chemistry.chemical_compound chemistry Phenylene Materials Chemistry symbols Perpendicular Molecule Lamellar structure Raman scattering
Zdroj:	Macromolecular Rapid Communications. 20:431-434
ISSN:	1521-3927 1022-1336
DOI:	10.1002/(sici)1521-3927(19990801)20:8<431::aid-marc431>3.0.co;2-r
Popis:	Two-arm poly(ethylene oxide) fractions (PEOs) with arm lengths of 2 220 g/mol were synthesized via a reaction using terephthaloyl (1,4-), isophthaloyl (1,3-) and phthaloyl (1,2-) dichorides as coupling agents. The center of each molecule thus includes a phenylene group as a configurational defect, and they are excluded to the crystal folded basal surfaces. In the lamellar crystals with the once-folded overall molecular conformation, observations of surface-enhanced Raman scattering experiments show that only the in-plane vibration modes are selectively enhanced. This implies that the arrangement of phenylene groups adopts a “stand-up” orientation on the basal surface, i. e., the π plane of phenylene groups in the defects is perpendicular to the lamellar basal surface.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::2a1616f0d2e310d788aa43ae2a1904f2 https://doi.org/10.1002/(sici)1521-3927(19990801)20:8<431::aid-marc431>3.0.co Zobrazit plný text záznamu Plný text