Molecular weights by light scattering in macromolecules solutions. Large deviations observed between a new method and the classical method

Beignon, M.; Bamba, S.; Evaina, D. Le Goff K.; Proutière, A.

doi:10.1016/s0022-2860(98)00614-0

Cited by 3 publications

(9 citation statements)

References 13 publications

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“…11,12,16,17,20 Studies have also been carried out with light scattering [21][22][23][24][25][26] and have concluded that MALLS (multiangle laser light scattering) can be used for the determination of the molecular weight and the molecular weight distribution of lignins. MALLS is an absolute molecular weight technique that is based on the intensity of the light that is scattered when a laser passes through a sample.…”

Section: Introductionmentioning

confidence: 99%

Propensity of Lignin to Associate: Light Scattering Photometry Study with Native Lignins

et al. 2008

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Many studies of lignins in solution invoke association and aggregation phenomena to explain their solution behavior (e.g., reprecipitation onto pulp fibers, condensation, etc.). Following their colloidal (apparent) molecular weights in solution as a function of time allows us to explore observable dissociation phenomena. These measurements were carried out using multiple angle laser light scattering (MALLS) photometry in the static mode. The challenges and opportunities of measuring the specific refractive index increment (dn/dC) of lignin solutions and determining the kinetics of the dissociation process were thus investigated. Hardwood and softwood representative lignins were isolated, and method for their full dissolution in THF was further developed, which then lead to accurate dn/dC values being obtained as a function of time. When coupled to additional work using light scattering static measurements and Zimm plots for the same solutions, this effort offers insight into the aggregation and ensuing dissociative events that operate within the lignin macromolecules.

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Section: Introductionmentioning

confidence: 99%

Propensity of Lignin to Associate: Light Scattering Photometry Study with Native Lignins

et al. 2008

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“…• to true values for molecular weight determination from Rayleigh light scattering and refraction in liquids. − …”

Section: Introductionmentioning

confidence: 99%

“…Molecular weight values deduced by any formula should not be dependent on the solvent. When using different solvents, Beignon et al found that in some cases, M values calculated by the CZ formula were several times higher than in toluene. In fact, there is a flaw in the CZ formula: when the refractive index, n , of dilute solutions slightly depends on the addition of polymer, that formula leads to overestimated values of M (and even to infinite values if there is no dependence at all!…”

Section: Introductionmentioning

confidence: 99%

Comparison of Proutière and Carr−Zimm Theories for Static Light-Scattering Molecular Weight Determination: Application to Surfactants in Solution

Evain¹,

Illien²,

Chabanel³

et al. 2007

J. Phys. Chem. B

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Proutière's theory of molecular weight (M) determination by Rayleigh scattering has been tested on surfactants in solution, and it has been compared to the classical Carr-Zimm (CZ) method. Both methods make use of time-averaged scattering intensity, refractive index, and density measurements. Monoethers of poly(ethylene glycol) samples have been studied in the range 0.33-4.67 kg/mol of M. Under those conditions, it has been shown that Proutière's method leads to a far better agreement with formula weight (M) values than the CZ method because Proutière theory takes into account the specific mean polarizability of the solvent and derivative of the solution density with respect to the solute mass concentration, which is counter to CZ theory.

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“…[13] These measurements provide weight-average molar mass M w and the socalled z-average square radius of gyration R 2 g D E z together with the second virial coefficient A 2 . Since 1996, Proutire and coworkers [14][15][16][17][18] have applied a new theory to dilute solutions to obtain M w and have explained several flaws in classical theory. These flaws are particularly enhanced for solutions with small refractive-index increments.…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, in many cases they are only assumed values deduced through the CZ equation for known M 2 values. [29] For these reasons and because the CZ equation is questionable, [14][15][16][17][18] the need for an experimental absolute Rayleigh ratio is a drawback of CZ equations.…”

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confidence: 99%

Molar Mass, Radius of Gyration and Second Virial Coefficient from new Static Light Scattering Equations for Dilute Solutions: Application to 21 (Macro)molecules

Illien

Ying

2009

ChemPhysChem

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New static light scattering (SLS) equations for dilute binary solutions are derived. Contrarily to the usual SLS equations [Carr-Zimm (CZ)], the new equations have no need for the experimental absolute Rayleigh ratio of a reference liquid and solely rely on the ratio of scattered intensities of solutions and solvent. The new equations, which are based on polarizability equations, take into account the usual refractive index increment partial differential n/partial differential rho(2) complemented by the solvent specific polarizability and a term proportional to the slope of the solution density rho versus the solute mass concentration rho(2) (density increment). Then all the equations are applied to 21 (macro)molecules with a wide range of molar mass (0.2500 kg mol(-1)), for which the scattered intensity is no longer independent of the scattering angle, the new equations give the same value of the radius of gyration as the CZ equation and consistent values of the second virial coefficient.

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Molecular weights by light scattering in macromolecules solutions. Large deviations observed between a new method and the classical method

Cited by 3 publications

References 13 publications

Propensity of Lignin to Associate: Light Scattering Photometry Study with Native Lignins

Propensity of Lignin to Associate: Light Scattering Photometry Study with Native Lignins

Comparison of Proutière and Carr−Zimm Theories for Static Light-Scattering Molecular Weight Determination: Application to Surfactants in Solution

Molar Mass, Radius of Gyration and Second Virial Coefficient from new Static Light Scattering Equations for Dilute Solutions: Application to 21 (Macro)molecules

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