Light-scattering sedimentation

W. Brown, R. Johnsen, P. Stilbs, B. Lindman. Size and shape of nonionic amphiphile (Ci2Eg) micelles in dilute aqueous solutions as derived from quasielastic and intensity of light scattering, sedimentation and pulsed-field-gradient nuclear magnetic resonance self-diffusion data. J Phys Chem 87 4548-4553, 1983. 

The various physical methods in use at present involve measurements, respectively, of osmotic pressure, light scattering, sedimentation equilibrium, sedimentation velocity in conjunction with diffusion, or solution viscosity. All except the last mentioned are absolute methods. Each requires extrapolation to infinite dilution for rigorous fulfillment of the requirements of theory. These various physical methods depend basically on evaluation of the thermodynamic properties of the solution (i.e., the change in free energy due to the presence of polymer molecules) or of the kinetic behavior (i.e., frictional coefficient or viscosity increment), or of a combination of the two. Polymer solutions usually exhibit deviations from their limiting infinite dilution behavior at remarkably low concentrations. Hence one is obliged not only to conduct the experiments at low concentrations but also to extrapolate to infinite dilution from measurements made at the lowest experimentally feasible concentrations. 

Coil dimensions Static light scattering, sedimentation measurements, small angle X-ray, solution viscosity... 

Osmotic pressure other colligative properties Light scattering sedimentation velocity Intrinsic viscosity... 

Size Shape Light scattering sedimentation Size, shape, mass of molecule. 

D. Slootmaekers, J. A. P. P. Dijk, F. A. Varkevisser, C. J. Bloys van Treslong, and H. Reynaers, Molecular characterization of k- and A-carrageenan by gel permeation chromatography, light scattering, sedimentation analysis and osmometry, Biophys. Chem., 41 (1991) 51-59. 

A summary of degrees of polymerization reported for hardwood xylans and the methods used for their determination, together with isolation procedures, yields, and viscosity data, is presented in Table V. The methods used include osmometry, light-scattering, sedimentation equilibrium, and sedimentation-diffusion (not listed). Recourse has also frequently been had to chemical methods for determining chain length. These methods are, however, far less reliable than physical techniques, and they will not be... 

Structure, M, and shape Static light scattering, dynamic light scattering, sedimentation measurements, small-angle X-ray, solution viscosity, imaging methods in situ) AFM, cryo (HR-)TEM, electron tomography)... 

The particle size distribution is usually measured by BS 410 sieves down to 45 pm and by laser light scattering, sedimentation, or electrical (Coulter) techniques for particles finer than this. The cement must be suspended in a nonaqueous solvent such as dried isopropyl or butyl alcohols. SEM in conjunction with... 

Laser diffraction Dynamic light scattering Sedimentation Bectrozone sensing Image analysis Sieving... 

The determination of the theta temperature by several techniques, such as intrinsic viscosity, phase equilibria, osmometry, light scattering, sedimentation equilibrium, and cloud point titration has been discussed comprehensively in a number of sources [1,14—16]. The influence of... 

Physical characteristics. pH, density, viscosity, turbidity, refractive index, light scattering, sedimentation rate by ultracentrifugation. 

Light scattering. Sedimentation diffusion. Calculated by using the values obtained from Equation (56) for [ /]. Data from refs 45 and 46. 

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