Self-Diffusion in Concentrated Solutions of Polystyrene in Toluene:  No Evidence for Large-Scale Heterogeneities

1999 ◽  
Vol 32 (7) ◽  
pp. 2382-2383 ◽  
Author(s):  
G. Fleischer
Keyword(s):  
Large Scale ◽  
Concentrated Solutions ◽  
Self Diffusion

scholarly journals The analysis of intermolecular interactions in concentrated hyaluronan solutions suggest no evidence for chain–chain association

2000 ◽  
Vol 350 (1) ◽  
pp. 329-335 ◽  
Author(s):  
Phillip GRIBBON ◽  
Boon Chin HENG ◽  
Timothy E. HARDINGHAM
Keyword(s):  
Fluorescence Recovery After Photobleaching ◽  
Hydrodynamic Radius ◽  
Hydrophobic Interactions ◽  
Lateral Diffusion ◽  
Tracer Diffusion ◽  
Dilute Solution ◽  
Concentrated Solutions ◽  
Chain Flexibility ◽  
Self Diffusion ◽  
Confocal Fluorescence

Confocal fluorescence recovery after photobleaching (confocal-FRAP) was used to examine the influence of electrolytes (NaCl, KCl, MgCl2, MnCl2 and CaCl2) on the network and hydrodynamic properties of fluoresceinamine-labelled hyaluronan (FA-HA) at concentrations up to 10mg/ml. Self and tracer lateral diffusion coefficients showed that in Ca2+ and Mn2+, FA-HA (830kDa) was more compact than in Mg2+, Na+ or K+. These results were correlated with changes in the hydrodynamic radius of HA, determined by multi-angle laser-light-scattering analysis in dilute solution, which was smaller in CaCl2 (36nm) than in NaCl (43nm). The permeability of more concentrated solutions of HA (< 10mg/ml) to FITC-dextran tracers (2000kDa) was higher in CaCl2. The properties of HA in urea (up to 6M) were investigated to test for hydrophobic interactions and also in ethanol/water (up to 62%, v/v). In both, there was reduced hydrodynamic size and increased permeability to FITC-dextran, suggesting increased chain flexibility, but it did not show the changes predicted if chain–chain association was disrupted by urea, or enhanced by ethanol. Oligosaccharides of HA (HA20–26) also had no effect on the self diffusion of high-molecular-mass FA-HA (830kDa) solutions, or on dextran tracer diffusion, showing that there were no chain–chain interactions open to competition by short-chain segments. The results suggest that the effects of electrolytes and solvent are determined primarily by their effect on HA chain flexibility, with no evidence for association between chain segments contributing significantly to the major properties.

Pulsed and Steady Field Gradient NMR Diffusion Measurements in Polymers

1985 ◽  
Vol 58 (3) ◽  
pp. 527-560 ◽  
Author(s):  
Ernst D. von Meerwall
Keyword(s):  
Spin Echo ◽  
Concentrated Solutions ◽  
Free Volume Theory ◽  
Polymer Systems ◽  
Polymer Molecules ◽  
Self Diffusion ◽  
Semidilute Solutions ◽  
Nmr Diffusion ◽  
Nmr Methods ◽  
And Diffusion

Abstract Some twenty years after the development of the steady and pulsed gradient spin-echo NMR methods of measuring self-diffusion, these techniques are now maturing and experiencing a surge of interest, much of it concentrated on polymer systems. The methods are briefly reviewed here, together with the most important results in polymers, with particular concentration on work described within the last few years. The research is divisible into three categories: diffusion of diluent and penetrant molecules in rubbery high polymers, diffusion of polymer molecules in dilute and semidilute solutions with liquid solvents, and diffusion of macromolecules dissolved in concentrated solutions or melts of equivalent or different polymers of arbitrary molecular weight. The review includes the main theoretical interpretations of the experiments, particularly the free-volume theory in its various forms and power-law behaviors postulated by recent refinements of tube/reptation and scaling theory. This article represents an updated elaboration of an earlier review.

scholarly journals The Self-Diffusion Coefficients of Myoglobin and Hemoglobin in Concentrated Solutions

1972 ◽  
Vol 247 (3) ◽  
pp. 895-901 ◽  
Author(s):  
Valentina Riveros-Moreno ◽  
Jonathan B. Wittenberg
Keyword(s):  
Diffusion Coefficients ◽  
The Self ◽  
Concentrated Solutions ◽  
Self Diffusion

Self‐diffusion and viscoelasticity of concentrated solutions of linear polystyrene in dibutyl phthalate (abstract)

1991 ◽  
Vol 35 (4) ◽  
pp. 708-708
Author(s):  
Masahiro Kishine ◽  
Norio Nemoto ◽  
Tadashi Inoue ◽  
Kunihiro Osaki
Keyword(s):  
Dibutyl Phthalate ◽  
Concentrated Solutions ◽  
Self Diffusion

scholarly journals Self-Diffusion and Viscoelasticity of Concentrated Solutions of Linear Polystyrene in Dibutyl Phthalate

1990 ◽  
Vol 18 (3) ◽  
pp. 133-139 ◽  
Author(s):  
Masahiro KISHINE ◽  
Norio NEMOTO ◽  
Tadashi INOUE ◽  
Kunihiro OSAKI
Keyword(s):  
Dibutyl Phthalate ◽  
Concentrated Solutions ◽  
Self Diffusion

Self-diffusion and sedimentation of dextran in concentrated solutions

1982 ◽  
Vol 20 (10) ◽  
pp. 1771-1780 ◽  
Author(s):  
W. Brown ◽  
P. Stilbs ◽  
R. M. Johnsen
Keyword(s):  
Concentrated Solutions ◽  
Self Diffusion
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