Study of aqueous dextran solutions under high pressures and different temperatures by dynamic light scattering

Stanković, Ranka; Jovanović, Slobodan V.; Ilić, Lj.; Nordmeier, E. H.; Lechner, M. D.

doi:10.1016/0032-3861(91)90008-7

Cited by 16 publications

(11 citation statements)

References 15 publications

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“…Taking our film thickness to be on the order of 0.1 cm, the model fit yields values for the diffusion coefficients of order 10 À5 cm 2 /s for aspirin, 10 À6 cm 2 /s for caffeine and 10 À8 cm 2 /s for dextran. Considering the significant approximations involved and the sensitivity to the (unmeasured) value of the film thickness due to the scaling of the fit coefficient as h 2 , these values are in relatively good agreement with the published diffusion coefficient values for all three molecules [32][33][34][35][36].…”

Section: Uncoated Filmssupporting

confidence: 73%

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Controlling surface porosity and release from hydrogels using a colloidal particle coating

Rosenberg

Dan

2010

Journal of Colloid and Interface Science

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Section: Uncoated Filmssupporting

confidence: 73%

“…Literature values suggest that FITC-dextran with MW similar to ours, in water, should have a diffusion coefficient of order 10 À7 cm 2 /s [34][35][36][37]. However, this value would be reduced when the media contains polymer chains [35].…”

Section: Uncoated Filmsmentioning

confidence: 83%

Controlling surface porosity and release from hydrogels using a colloidal particle coating

Rosenberg

Dan

2010

Journal of Colloid and Interface Science

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“…The critical concentration at which this transition occurs depends on the molecular weight, or degree of polymerization, of the dextran used. For dextran of ∼2 × 10 6 Da, used in this study, the critical concentration in which a transition to a structured matrix occurs is 0.8–1.2% (see Granath, 1958; Graessley, 1980; Smit et al ., 1992; Stankovic et al ., 1991). One would expect a sharp change in cell velocity at concentrations above ∼1%.…”

Section: Resultsmentioning

confidence: 99%

Motility modes of Spiroplasma melliferum BC3: a helical, wall‐less bacterium driven by a linear motor

Gilad¹,

Porat

Trachtenberg³

2003

Molecular Microbiology

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“…This follows from the cumulant expansion19•26•27 of gft) = ^ ) * " -' 1 + m//2! + ...] (10) The parameter is called the first cumulant. As shown by Akcasu and Gurol,20 f can be calculated exactly without knowing the space-time correlation function with the result…”

Section: Dynamicmentioning

confidence: 99%

Static and dynamic light-scattering solution behavior of pullulan and dextran in comparison

Nordmeier¹

1993

J. Phys. Chem.

140

126

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The conformational and dynamic behavior of fractionated samples of pullulan and dextran has been studied by means of static and dynamic light scattering. Measurements were carried out in water and in some 9 solvents at various temperatures. Static light scattering yields the molar mass, M,, the radius of gyration, (S2)fi5, and the second virial coefficient, Az. From dynamic light scattering we obtained the translational diffusion coefficient, DZ,o, and the second hydrodynamic virial coefficient, kD,2. Analysis of the molar mass dependencies of (S2)20.5, A2, and DZ,o clearly exhibits that pullulans are linear and dextrans are branched molecules. The ratio g = (S2)z,t,/ (S2)2,1 suggests that branching becomes more pronounced when the molar mass increases. However, the g factor says nothing about the exact branching structure. To obtain such information, the particle scattering factors, P(q),, of dextran were compared with model calculations of nonrandom ABC polycondensates and soft spheres. Using Kratky plots, where q2P(& is plotted vs q, we find that the soft-sphere model describes the experiment satisfactorily. Interestingly, the same result is proposed by the discussion of the ratiop = (SZ),O.5/ Rh, where Rh represents the hydrodynamic radius. Analysis of the second virial coefficients shows that the A2 values of pullulan are larger than those of the corresponding dextrans of the same molar mass. This effect is discussed in terms of the interpenetration function, #, and thegfactor. It is found that the intra-and intermolecular segment interactions can be described simultaneously by a universal function $. For the linear pullulans, a two-parameter theory is satisfactory, while for the branched dextrans one more parameter is needed. Finally, the concentration dependence of the diffusion coefficient, &,o, was investigated. It is found that there exists a r a t i o x = s/& at which the volume fraction virial coefficient, kx,, becomes zero. This value of xseparates the good solvent behavior, where D2,0 increases with concentration, from the poor solvent behavior, where it decreases with concentration. Note that s is the thermodynamically effective radius of interaction. At the 9 state the kla values become identical for pullulan and dextran, and the limiting value -2.2 of the soft sphere is reached. However, refined theories are needed to explain these effects in more detail.

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Study of aqueous dextran solutions under high pressures and different temperatures by dynamic light scattering

Cited by 16 publications

References 15 publications

Controlling surface porosity and release from hydrogels using a colloidal particle coating

Controlling surface porosity and release from hydrogels using a colloidal particle coating

Motility modes of Spiroplasma melliferum BC3: a helical, wall‐less bacterium driven by a linear motor

Static and dynamic light-scattering solution behavior of pullulan and dextran in comparison

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