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Titolo:
Structure, diffusivity and linear rheology of sodium ether dodecylsulfate in aqueous solutions - (I)
Autore:
Clancy, SF; Paradies, HH;
Indirizzi:
Univ Appl Sci Biotechnol & Phys Chem, D-58690 Iserlohn, Germany Univ Appl Sci Biotechnol & Phys Chem Iserlohn Germany D-58690 n, Germany Unit 22, Stamford, CT 06906 USA Unit 22 Stamford CT USA 06906Unit 22, Stamford, CT 06906 USA Univ Gesamthsch Paderborn, D-33095 Paderborn, Germany Univ Gesamthsch Paderborn Paderborn Germany D-33095 5 Paderborn, Germany
Titolo Testata:
ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS
, volume: 215, anno: 2001,
parte:, 4
pagine: 483 - 513
SICI:
0942-9352(2001)215:<483:SDALRO>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
ANGLE NEUTRON-SCATTERING; RODLIKE MICELLES; CORRELATION SPECTROSCOPY; PERSISTENCE LENGTH; CHLORIDE SOLUTIONS; WORMLIKE MICELLES; SULFATE MICELLES; LIVING POLYMERS; FLEXIBILITY; SURFACE;
Keywords:
static & dynamic light scattering; sodium laurylethersulfate; scaling laws; rheology; decay time distribution;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
62
Recensione:
Indirizzi per estratti:
Indirizzo: Paradies, HH Univ Appl Sci Biotechnol & Phys Chem, Frauenstuhlweg 31, D-58690 Iserlohn,Germany Univ Appl Sci Biotechnol & Phys Chem Frauenstuhlweg 31Iserlohn Germany D-58690
Citazione:
S.F. Clancy e H.H. Paradies, "Structure, diffusivity and linear rheology of sodium ether dodecylsulfate in aqueous solutions - (I)", Z PHYS CHEM, 215, 2001, pp. 483-513

Abstract

Static and dynamic light scattering measurements have been performed on dilute and semidilute solutions of sodium ether dodecylsulfate (sodium laurylethersulfate, RO(CH2CH2O)(2)SO3- with R=C-12) in the presence of NaCl at 25degreesC and were combined with theology measurements. At dilute concentrations (0.92-1.82C*) with C* = [3M(r)/4 pi((R-g(2))(z))N-3(A); in the presence of 0.05 M NaCl sodium ether dodecylsulfate (SLES) show a first normal mode of the chain entanglement which agrees reasonable well with that of a free draining Zimm-model. The slow component which is Q(2) independent has a larger amplitude than the fast component which is Q(2) dependent, and reflects the disruption and/or coalescence kinetics of SLES-aegregates. Increasing the salt concentrations or the SLES-concentrations resulted in the formation of isotropic rodlike micelles. The light scattering results were supplemented with theology experiments revealing the different transition statesof SLES-micelles, too. In addition, above C > C*, with C*= 0.15 (w/w) of SLES, the viscoelastic properties are described by an almost ideal Maxwellian behaviour. The rheological data obtained are consistent with scaling lawsof the SLES concentration where the exponents are close to those predictedfrom recent stress relaxation models applied to living polymers. At high angular frequency, the complex modulus is explained in terms of a cross overbetween the regimes of reversible scission and of breathing of the polymer-like chains. The total average chain lengths of the SLES-aggregates was found to increase with SLES concentration, e.g. L(empty set) congruent to phi(0.37-0.44)(SLES) with empty set (SLES) expressed as weight percent of surfactant, measured between 0.05%-15%, encompassing both dilute and semidilute regimes. The observed findings are different from reports on cationic surfactants of the cetylpyridinium or cetyltrimethyammonium ion types in the presence of strongly bound counterions, e.g. salicylate or high salt, respectively. Moreover, the experiments conducted in the presence of n-dodecanol as a contamination of the SLES reveal distinct differences to previous reported experiments, missing all the transitions of this surfactant. In addition no indication has been found for intramolecularly crosslinking or connections between entangled chains in the presence of 0.1 M NaCl. However. at high salt concentrations a transition to a rod-like structure of SLES has been observed with hydrodynamic parameters of R-O = 260 Angstrom, N-agg congruent to 3000, L congruent to 900 Angstrom and d = 45.0 Angstrom.

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Documento generato il 12/07/20 alle ore 08:38:19