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Titolo:
Hydrocarbon chain conformation in an intercalated surfactant monolayer andbilayer
Autore:
Venkataraman, NV; Vasudevan, S;
Indirizzi:
Indian Inst Sci, Dept Inorgan & Phys Chem, Bangalore 560012, Karnataka, India Indian Inst Sci Bangalore Karnataka India 560012 560012, Karnataka, India Indian Inst Sci, Solid State & Struct Chem Unit, Bangalore 560012, Karnataka, India Indian Inst Sci Bangalore Karnataka India 560012 560012, Karnataka, India
Titolo Testata:
PROCEEDINGS OF THE INDIAN ACADEMY OF SCIENCES-CHEMICAL SCIENCES
fascicolo: 5-6, volume: 113, anno: 2001,
pagine: 539 - 558
SICI:
0253-4134(200110/12)113:5-6<539:HCCIAI>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
NORMAL-ALKYL CHAINS; H STRETCHING MODES; LAYERED SILICATES; SPECTROSCOPY; ADSORPTION; MOLECULES; MOTION; PHASES; FILMS; LONG;
Keywords:
intercalation; layered compound; surfactant assembly; conformation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
35
Recensione:
Indirizzi per estratti:
Indirizzo: Vasudevan, S Indian Inst Sci, Dept Inorgan & Phys Chem, Bangalore 560012, Karnataka, India Indian Inst Sci Bangalore Karnataka India 560012 taka, India
Citazione:
N.V. Venkataraman e S. Vasudevan, "Hydrocarbon chain conformation in an intercalated surfactant monolayer andbilayer", P I A S-CH, 113(5-6), 2001, pp. 539-558

Abstract

Cetyl trimethyl ammonium (CTA) ions have been confined within galleries oflayered CdPS3 at two different grafting densities. Low grafting densities are obtained on direct intercalation of CTA ions into CdPS3 to give Cd0.93PS3(CTA)(0.14). Intercalation occurs with a lattice expansion of 4.8 Angstrom with the interlamellar surfactant ion lying flat forming a monolayer. Intercalation at higher grafting densities was effected by a two-step ion-exchange process to give Cd0.93PS3(CTA)(0.14), with a lattice expansion of 26.5Angstrom. At higher grafting densities the interlamellar surfactant ions adopt a tilted bilayer structure. C-13 NMR and orientation-dependent IR vibrational spectroscopy on single crystals have been used to probe the conformation and orientation of the methylene 'tail' of the intercalated surfactant in the two phases. In the monolayer phase, the confined methylene chain adopts an essentially all-trans conformation with most of the trans chain aligned parallel to the gallery walls. On lowering the temperature, molecularplane aligns parallel, so that the methylene chain lies flat, rigid and aligned to the confining surface. In the bilayer phase, most bonds in the methylene chain are in trans conformation. It is possible to identify specificconformational sequences containing a gauche bond, in the interior and termini of the intercalated methylene. These high energy conformers disappear on cooling leaving all fifteen methylene units of the intercalated cetyl trimethyl ammonium ion in trans conformational registry at 40 K.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/04/20 alle ore 06:29:55