Electrophoretic light scattering

The present samples salt out in Nal solutions, only. For I the mobility is Hi= 8 10-4 cm2V 1 s 1. The polyion mobilities were measured by electrophoretic light scattering, shown in Fig. 11. Although at low salt np linearizes... 

Beside of the progress in the theory of a particle movement in the zetameter measurement cell, there was progress in particle measurement techniques. New models of zetameters enable automatic measurement of electrophoretic mobility on the basis of the shift of light wave scattered on the particle that moves in the electric field [82]. This technique is called photon correlation spectroscopy (PCS). To increase the sensitivity of the measurement, it is supported by multiangle electrophoretic light scattering (ELS). This combination, allows one also to measure the particle size distribution of the dispersed phase [83]. 

Thompson, R.G., Practical zeta potential determination using electrophoretic light scattering, Am. Lab., 24, 48, 1992. 

Electrophoretic light scattering (ELS) is commonly used to measure v. The electrophoretic mobility /r can be calculated from v and the known value of E according to Eq. (I). Theoretical models [ I.7-I0] that describe colloidal electrostatics and hydrodynamics can then be used to relate the measured values of n to particle electrical characteristics including surface charge density and surface electric potential. Because /r depends on the surface electrostatic properties but not particle bulk properties, ELS can characterize surface electrostatic properties exclusively for a wide range of colloidal materials. 

Dynamic light scattering (DLS) techniques measure the fluctuations in the scattered light intensity caused by the random Brownian motion of the dispersed particles. The use of a theoretical model of particle Brownian motion enables us to extract particle size from DLS data. Other dynamic light scattering techniques such as electrophoretic light scattering (ELS) study collective particle motions. Theoretical interpretation of ELS data leads to other particle properties such as electrophoretic mobility fi and zeta potential f. These techniques will be discussed in more detail in subsequent sections. 

Electrophoretic light scattering (ELS) is a subset of DLS (Section II.C.3) that is commonly used to measure the electrophoretic mobility /a of colloidal particles (Section I.A.2). ELS can be used to probe particle surface electrostatic properties via theoretical models of colloidal electrostatics and hydrodynamics that relate H to particle electrical characteristics. 

B.R. Ware, Electrophoretic Light Scattering., Adv. Colloid Interface Sci. 4 (1974) 1. (Review.)... 

Electrophoretic light-scattering is a technique which determines the electrophoretic velocities by measuring the Doppler shifts of scattered laser light. The electrophoretic mobility can be expressed by... 

Oja, T. Bott, S. Sugrue, S. Doppler electrophoretic light scattering analysis using the coulter DELSA 440. Coulter Electronics Luton, 1989. 

Hackley, V.A. et al.. A standard reference material for the measurement of particle mobility by electrophoretic light scattering, Colloids Surf. A, 98, 209, 1995. 

As an optical detection system, electrophoretic light scattering has been frequently used in recent years [4], In this case, the collected signal of the particles movement shifted to higher or lower frequencies depending on their charge. The frequencies are then converted to electrophoretic mobilities, velocities, and finally zeta potentials. 

Stabilization and destabilization studies on kaolin suspensions were performed in our group by means of various electrokinetic methods to follow the adsorption process of differently charged polyelectrolytes. The polyelectrolytes used were polycations such as the branched free polybase polyethyl-eneimine (PEI) and the linear PD ADM AC, and Na-poly aery late as polyanion, whereas the polycations are of different charge density. In Figures 4-7 results of electrophoretic light scattering experiments (Zetasizer 4, Malvern) of 0.05% (w/w) kaolin suspensions are presented (compare Ref. 24). 

Yamaguchi K., Hachiya K., Moriyama Y., Takeda K. Electrophoretic light scattering study of sodium dextran sulfate-lysozyme complex. J. Coll. Interf. Sci. 1996 179 249-254. 

Scattering methods provide detailed information about the structural parameters of colloidal particles. In the field of polyelectrolyte complexes, mainly light scattering techniques such as static, dynamic, and electrophoretic light scattering were employed. 

Electrophoretic light scattering measurements. If an electric held of strength E acts on an isolated charged particle of charge Q, it causes a motion, which is at a velocity u balanced by the friction force. For a sphere one obtains the simple expression... 

Li Y, Dubin PL, Havel HA, Edwards SH, Dautzenberg H. Electrophoretic light-scattering, dynamic light-scattering, and turbidimetry studies of the effect of polymer concentration on complex-formation between polyelectrolyte and oppositely charged mixed micelles. Macromolecules 1995 28 3098-3102. 

Chapter 13 includes a short introduction to the theory of nonequilibrium thermodynamics. A discussion of frames of reference in the definition of transport coefficients is given and a systematic theory of diffusion is presented. Fluctuations in electrolyte solutions are analyzed, and the parameters measured in electrophoretic light-scattering experiments are related to conductance and to the transference numbers—quantities usually measured in conventional electrochemistry. 

Fig. 5.8.7. Data for electrophoretic light-scattering experiment on a solution containing BSA, BSA dimers, and fibrinogen. (From Ware and Flygare, 1972, Fig. 4.)...

Fig. 6.3.1. A simulated electrophoretic light-scattering spectrum of a chemically reacting system...

This method of analysis may also be extended to the interpretation of electrophoretic light scattering from polydisperse systems. 

Another way to analyze paucidisperse systems by light scattering is to use external fields such as is done in the electrophoretic light-scattering technique described in Section (5.8). 

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