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Titolo:
Flow light scattering studies of polymer coil conformation in solutions inextensional flow
Autore:
Lee, EC; Muller, SJ;
Indirizzi:
Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA Univ Calif Berkeley Berkeley CA USA 94720 em Engn, Berkeley, CA 94720 USA Univ Calif Berkeley, Lawrence Berkeley Lab, Ctr Adv Mat, Berkeley, CA 94720 Univ Calif Berkeley Berkeley CA USA 94720 Ctr Adv Mat, Berkeley, CA 94720
Titolo Testata:
MACROMOLECULES
fascicolo: 10, volume: 32, anno: 1999,
pagine: 3295 - 3305
SICI:
0024-9297(19990518)32:10<3295:FLSSOP>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
ELONGATIONAL FLOW; 4-ROLL MILL; MACROMOLECULAR DYNAMICS; VELOCITY-GRADIENTS; RELAXATION-TIME; DNA MOLECULE; SHEAR-FLOW; BIREFRINGENCE; SPECTROSCOPY; DEGRADATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
47
Recensione:
Indirizzi per estratti:
Indirizzo: Muller, SJ Univ Calif Berkeley, Dept Chem Engn, Berkeley, CA 94720 USA Univ Calif Berkeley Berkeley CA USA 94720 rkeley, CA 94720 USA
Citazione:
E.C. Lee e S.J. Muller, "Flow light scattering studies of polymer coil conformation in solutions inextensional flow", MACROMOLEC, 32(10), 1999, pp. 3295-3305

Abstract

The dynamics of isolated polymer chains in dilute solution under steady, extensional flow were investigated by means of flow light scattering. Both the orientation and deformation of the chains during flow were determined byanalyzing the angular dependence of the scattered light intensity. The extensional flow field was imparted on the polymeric: fluids by a stagnation point flow in the center of a four-roll mill apparatus. The fluids studied were nearly monodisperse high molecular weight polystyrenes (HMPS) of various molecular weights dissolved in either the viscous solvent dioctyl phthalate (DOP) or a mixed solvent of low molecular weight polystyrene (LMPS) and dioctyl phthalate. The flow field in a Newtonian fluid of seeded glycerin was also examined by flow dynamic light scattering techniques and flow visualization to confirm the extensional flow field. Flow dynamic Light scattering and flow visualization results verified that the field generated by the four-roll mill was a reasonable approximation of planar extensional flow, under the conditions investigated. Flow (static) light scattering results confirmed that the polymer chains aligned completely with the stretch direction, as expected for this type of flow. The deformation of the chains, however, was significantly less than predicted by elastic dumbbell models. Also studied were the effects of molecular weight and solvent quality on the deformation of the polymer chains. Comparisons are drawn between polystyrene chains in the strong extensional flow field studied here and a steady shearing flow examined in a previous publication as well as with other studies inextensional flows.

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Documento generato il 27/10/20 alle ore 11:10:50