Dynamic light scattering. See

Control the size by dynamic light scattering (see Note 5). For measurements on a nanoZS (Malvern Instruments), dilute 5 pL of the particles obtained in a 500 pL cuve, start the measure in the automatic mode. 

This important relation is used to determine coil size from measured diffusion coefficient (for example, by dynamic light scattering—see Section 8.9, or by pulsed-field gradient NMR). The size determined from a measurement of diffusion coefficient is the hydrodynamic radius ------... 

As an example let us consider the apparent diffuaon constant measured by dynamic light scattering (see eqn (5.114)). First we use a dimensional analysis. The relevant parameters in the problem are b, c, N, kgT, and so is written as... 

Foam rheology has been a challenging area of research of interest for the yield behavior and stick-slip flow behavior (see the review by Kraynik [229]). Recent studies by Durian and co-workers combine simulations [230] and a dynamic light scattering technique suited to turbid systems [231], diffusing wave spectroscopy (DWS), to characterize coarsening and shear-induced rearrangements in foams. The dynamics follow stick-slip behavior similar to that found in earthquake faults and friction (see Section XU-2D). 

Direct measurements of equilibrium stress-strain isotherms of SAH are complicated by the gel softness. Nevertheless, a number of experiments on compression and tension of the gels has been reported (see, for example, Refs. [18, 21, 42]). The method of dynamic light scattering is free from such inconveniences... 

Particle size measurement is one of the essential requirements in almost all uses of colloids. However, our discussion in Section 1.5 makes it clear that this is no easy task, especially since even the definition of particle size is difficult in many cases. A number of techniques have been developed for measuring particle size and are well documented in specialized monographs (e.g., Allen 1990). Optical and electron microscopy described in the previous section can be used when ex situ measurements are possible or can be acceptable, but we also touch on a few nonintrusive methods such as static and dynamic light scattering (Chapter 5) and field-flow fractionation (see Vignette II Chapter 2) in other chapters. 

It is our objective in this chapter to outline the basic concepts that are behind sedimentation and diffusion. As we see in this chapter, gravitational and centrifugal sedimentation are frequently used for particle-size analysis as well as for obtaining measures of solvation and shapes of particles. Diffusion plays a much more prevalent role in numerous aspects of colloid science and is also used in particle-size analysis, as we see in Chapter 5 when we discuss dynamic light scattering. The equilibrium between centrifugation and diffusion is particularly important in analytical and preparative ultracentrifuges. 

Using dynamic light-scattering techniques, Lechner was able to prove that this effect is due to the tendency of PVA to agglomerate for more details see Kulicke, Bose, Bouldin. On the other hand, a decrease in viscosity has been obtained with no detectable change in the average molecular weight. 

High-pressure static and dynamic light scattering were used to closely examine the behavior of block copolymers of poly(vinyl acetate) (PVAc) and poly(l,l,2,2-tetrahydroperfluoroalkyl acrylate (PTAN) as a function of C02 density (Buhler et al., 1998). The phase diagram for PVAc-6-TAN shows three distinct phases as a function of polymer concentration and C02 density at a fixed temperature of 45 °C (see Figure 9.1). The block copolymer forms a precipitated phase at low C02 densities, spherical micelles at intermediate C02 densities, and unimers, or free polymer chains in solution, at high densities. The micelles-to-unimer transition was found to be very... 

DDBJ—see EMBL DLS—dynamic light scattering DM—donkey s milk DNA—deoxyribonucleic acid DNCB—2,4-dinitrochlorobenzene DSC—differential scanning calorimetry DTH—delayed cellular hypersensitivity DXMS—deuterium exchange mass spectrometry EAACI—European Academy of Allergology and Clinical Immunology EAR—early anaphylactic phase ECFA—eosinophil chemotactic factors of anaphylaxis ECP—eosinophil cationic protein EDN—eosinophil-derived neurotoxin eHF—extensively hydrolyzed formula ELISA—enzyme-linked immunosorbent assay... 

Dynamic light scattering may be used to determine the particle size distribution or molecular weight distribution In a wide variety of applications. See ref. (1) for discussion of this literature. 

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