Intrinsic viscosity of flexible macromolecules : transition from theta to collapsed state

Perzynski, R.; Delsanti, M.; Adam, M.

doi:10.1051/jphys:0198400450110176500

Cited by 23 publications

(16 citation statements)

References 25 publications

(50 reference statements)

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“…We must have AT > 8/N 1 ~~ to reach a significant collapse [3]. The final state has been widely studied experimentally [4][5][6][7][8] and theoreticallystarting from an idea of Stockmayer [9]. Here we shall use the simplest (mean field) theoretical description [10,11] to describe the collapse.…”

Section: Aims and Toolsmentioning

confidence: 99%

“…For a very long polystyrene chain (M = 107), taking AT/0 = 10-1 we arrive at time r~ ~ 1 millisecond. In practice, one would probably prefer pressure jumps to temperature jumps, especially for lower molecular weights M. Experimentally, in the PS/cyclohexane system (7,8), for AT/AT* > 40 and a molecular weight of 10', precipitation occurs at concentrations 5 10-5 g/cm3.…”

Section: Practical Aspectsmentioning

confidence: 99%

See 1 more Smart Citation

Kinetics of collapse for a flexible coil

de Gennes

1985

J. Phyique Lett.

226

255

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2014 Si on transfère tout à coup une chaine flexible depuis le point 03B8 vers une situation de mauvais solvant (par exemple, par un changement de température 0394T) elle s'effrondre en un temps 03C4c. Nous proposons ici une loi d'échelle pour 03C4c, basée sur un modèle de « saucisse gonflée », et prenant en compte les interactions hydrodynamiques. Nous trouvons 03C4c ~ 03C4R 0394T/03B8 où 03C4R est le temps de Rouse de la chaîne au point 03B8 : le temps 03C4c croit avec la profondeur de la trempe. Abstract. 2014 If a polymer chain is transferred abruptly from 03B8 conditions to bad solvent conditions (e.g. by a shift of temperature 0394T) it collapses with a certain characteristic time 03C4c. We propose a scaling structure for 03C4c, based on an « expanding sausage model », and taking into account the hydrodynamic interactions. We find that 03C4c ~ 03C4R 0394T/03B8 where 03C4R is the Rouse time of the 03B8 chain : the time 03C4c increases with the depth of quench.

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Section: Aims and Toolsmentioning

confidence: 99%

Section: Practical Aspectsmentioning

confidence: 99%

Kinetics of collapse for a flexible coil

de Gennes

1985

J. Phyique Lett.

226

255

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“…Relaxation of the solvent was achieved by random displacement Monte Carlo moves. Statistics for conformational properties, i.e., mean square end-to-end distance, ͗R 2 ͘, and mean square gyration radius, ͗R g 2 ͘, were collected for O(10 7 ) steps after an equilibration period of at least 5ϫ10 6 steps. This recipe gives O(10 6 ) successful chain moves.…”

Section: A Canonical Ensemble Simulationsmentioning

confidence: 99%

“…On the experimental side, there has been a great deal of work on the dynamic and static properties of dilute polymer solutions in good, theta, and poor solvents near the UCST. 1,6 As is well-known, polymer solutions also exhibit lower critical solution temperature ͑LCST͒, or thermally induced, phase separation where phase splitting is induced by raising temperature. LCSTs have been observed in strongly interacting polar mixtures, for example aqueous solutions, as well as in weakly interacting nonpolar polymer solutions.…”

Section: Introductionmentioning

confidence: 99%

Relationship between polymer chain conformation and phase boundaries in a supercritical fluid

Luna‐Bárcenas

Meredith

Sánchez

et al. 1997

The Journal of Chemical Physics

130

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We investigate the solvent density driven changes in polymer conformation and phase behavior that occur in a supercritical fluid, with a particular emphasis on conditions near the lower critical solution temperature ͑LCST͒ phase boundary. Using continuous space Monte Carlo simulations, the mean square end-to-end distance (R) and radius of gyration (R g ) are calculated for a single chain with 20 Lennard-Jones segments in a monomeric solvent over a broad range of densities and temperatures. The chains collapse as temperature increases at constant pressure, or as density decreases at constant temperature. A minimum in R and R g occurs at a temperature slightly above the coil-to-globule transition temperature ͑C-GTT͒, where the chain adopts a quasi-ideal conformation, defined by the balance of binary attractive and repulsive interactions. Expanded ensemble simulations of finite-concentration polymer-solvent mixtures reveal that the LCST phase boundary correlates well with the single chain C-GTT. At temperatures well above the LCST, the chain expands again suggesting an upper critical solution temperature ͑UCST͒ phase boundary above the LCST.

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“…Experiments on the transition from a single polymer coil behavior in the O state to a globule in the collapsed state did not agree with one another (Slagowski, Tsai & Mclntyre, 1976;Nierlich, Cotton & Farnoux, 1978;Bauer & UUman, 1980;Pritchard & Caroline, 1980;Miyaki & Fujita, 1981;Oyama, Shiokawa & Baba, 1982;Post & Zimm, 1982;Stepanek, Konak & Sedlacek, 1982;Perzynski, Adam & Delsanti, 1982;Perzynski, Delsanti & Adam, 1984;Vidakovic & Rondelez, 1984;Selser, 1985;Chu, Park, Wang & Wu, 1987). If we consider the collapsed state based on the radius of gyration Rg from static lightscattering measurements, recent experiments on the PS/CY system below the Ou temperature and the PS/methyl acetate (MA) system both below the Ov temperature and above the lower theta temperature (OD showed that a plateau 3 1/2 region [with constant (es IzlMw )3 could be reached in a plot of scaled expansion factor 3 1/2 o~ IzlMw versus scaled reduced temperature I'rlM 1/2 where ~= Rg(T)/Rg(O) and z = IT-O[/O.…”

Section: Coil-to-globule Transitionmentioning

confidence: 99%

Critical phenomena and polymer coil-to-globule transition

Chu¹,

Xu²,

Wang³

et al. 1988

J Appl Cryst

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Small-angle scattering techniques including laser light scattering (LLS), small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) have been useful tools to measure the static and dynamic properties (in terms of critical fluctuations) of fluids, fluid mixtures, polymer and micellar solutions, polymer blends and metallic alloys. A brief review is given of recent results in critical-phenomena experiments using small-angle scattering techniques. Topics of current interest are pointed out, and a guide to the vast literature on critical opalescence is provided. Coil-toglobule transition in polymer solutions has been a classic experimental challenge over the past decade. In order to succeed in reaching the collapsed regime, it becomes important to realize that single coil contraction of a linear polymer molecule in solution takes place in the neighborhood of phase separations. By using the recent development of a small-angle lightscattering spectrometer and by taking advantage of a successful polymer fractionation experiment, the transition behavior of linear polystyrene in cyclohexane from the 69 state to the collapsed regime can be characterized based on both the radius of gyration and the hydrodynamic radius.

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Intrinsic viscosity of flexible macromolecules : transition from theta to collapsed state

Cited by 23 publications

References 25 publications

Kinetics of collapse for a flexible coil

Kinetics of collapse for a flexible coil

Relationship between polymer chain conformation and phase boundaries in a supercritical fluid

Critical phenomena and polymer coil-to-globule transition

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