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Titolo:
Thermodynamics of molecular self-assembly of cationic gemini and related double chain surfactants in aqueous solution
Autore:
Bai, GY; Wang, JB; Yan, HK; Li, ZX; Thomas, RK;
Indirizzi:
Chinese Acad Sci, Inst Chem, Ctr Mol Sci, Beijing 100080, Peoples R China Chinese Acad Sci Beijing Peoples R China 100080 100080, Peoples R China Univ Oxford, Phys & Theoret Chem Lab, Oxford OX1 3QZ, England Univ OxfordOxford England OX1 3QZ ret Chem Lab, Oxford OX1 3QZ, England
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 15, volume: 105, anno: 2001,
pagine: 3105 - 3108
SICI:
1520-6106(20010419)105:15<3105:TOMSOC>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
ALKANEDIYL-ALPHA,OMEGA-BIS(DIMETHYLALKYLAMMONIUM BROMIDE) SURFACTANTS; CRITICAL MICELLE CONCENTRATION; ANGLE NEUTRON-SCATTERING; AIR-WATER-INTERFACE; DIMERIC SURFACTANTS; SPACER CHAIN; AGGREGATION BEHAVIOR; MICELLIZATION; MODEL; LENGTH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Yan, HK Chinese Acad Sci, Inst Chem, Ctr Mol Sci, Beijing 100080, Peoples R China Chinese Acad Sci Beijing Peoples R China 100080 Peoples R China
Citazione:
G.Y. Bai et al., "Thermodynamics of molecular self-assembly of cationic gemini and related double chain surfactants in aqueous solution", J PHYS CH B, 105(15), 2001, pp. 3105-3108

Abstract

Microcalorimetric measurements have been made on the series of gemini surfactants [CMH2M+1(CH3)(2)N-(CH2)(S)N(CH3)(2)CMH2M+1] Br-2, designated CMCSCMBr2, where M and S indicate the numbers of carbons in the side chains and spacer respectively, for M = 12 and S = 3, 4, 6, 8, 10, 12. For comparison, parallel measurements have been made on the series of double-chain, singly charged surfactants dodecyldimethyl-alkylammoninm bromides, designated as C12CNBr With N = 1; 2, 4, 6, 8, 10, 12, where N is the number of carbons in the secondary alkyl chain. The choice of this second series was to compare each CMCSCMBr2 with its nearest equivalent monomer C12CS/2Br The values of the critical micelle concentrations (cmc) were found to be in good agreement with other measurements, showing a maximum at S = 4-6 for the geminis anda nonlinear variation with chain length for the C12CNBr series. For both series of surfactants, the enthalpies of micellization, DeltaH(mic), are allexothermic and show a marked minimum in magnitude at S = 4-6 or N = 4-6. The variation of DeltaH(mic) and DeltaS(mic) across both series shows that the balance between enthalpic and entropic contributions to the process of micellization changes substantially with S or N.

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Documento generato il 30/09/20 alle ore 01:05:59