Viscometry, light scattering and

Studies on the hydrodynamic properties of the same samples by dynamic light scattering and viscometry confirmed the conclusions of the static methods. Decreased diffusion coefficients and kD values, where kD is the coefficient of the concentration dependence of D (kD=2A2M-kfv), were observed for the zwitteri-... 

Berth, G. (1992), Methodical aspects of characterization of alginate and pectate by light scattering and viscometry coupled with GPC. Carbohydr. Polym. 19 1-9. 

The latter methods were almost fully substituted with size exclusion chromatography, though especially light scattering and viscometry are often used for detection in SEC (see section 11.7.3.2, Mobile Phases and Detectors for Size Exclusion Chromatography). 

Advanced SEC analytical techniques take advantage of online light scattering and viscometry [IV A]. With the SEC calibrated for the product of [rj] times M versus elution time for a particular polymer species, together with [rj]Br or Myf measurements, one can calculate g factors as the ratio of the measured intrinsic viscosity to the value of [r/j calculated for the corresponding linear polymer (i.e., linear polymer that would have eluted at the same time). 

Molecular mass averages for fractions and unfractionated P(VC-VAc) copolymers were calculated by using the universal calibration curve, and were compared with those obtained by light scattering and viscometry. The mean difference was + 6-7%. 

STUDY OF INTRA-MOLECULAR CROSSLINKING OF POLYACRYLAMIDE IN Cr(III)-POLYACRYLAMIDE GELATION BY SIZE-EXCLUSION CHROMATOGRAPHY, LOW-ANGLE LASER LIGHT SCATTERING, AND VISCOMETRY... 

The formation of CTAB rod-like micelles with molecular weight of 10 in the presence of KBr was reported by Debye and Anacker [42], About a decade ago, the salt-induced sphere-rod transition of alkyltrimethy-lammonium halides was extensively studied with the use of static light scattering and viscometry [43-46]. The formation of surfactant micelles in low-molecular electrolyte solution has been described as a two-step process at first, primary spherical micelles were formed and then, with further increase of salt concentration, micelles reorganized to the secondary rod-like shape [47]. It was also concluded that the salt-induced sphere-rod transition of the surfactant micelles is not caused by the change in water structure [48]. 

Modem SEC instruments in R D are often equipped with three or four detectors in series. However, this does not minimize the required user input and knowledge of the single methods applied (SEC, light scattering, and viscometry) is indispensable. Additional system parameters, such as the inter-detector delay, need to be determined carefully as they influence the results [13]. In addition, band broadening due to use of several detectors can be a problem [14-16]. 

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