Fractal Concepts And Aggregation Of Iron Oxides

1990 ◽  
Vol 180 ◽  
Author(s):  
R. Amal ◽  
J.A. Raper ◽  
T.D. Waite
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Iron Oxides ◽  
Aggregate Size ◽  
Fractal Dimensions ◽  
Aggregation Kinetics ◽  
Diffusion Limited ◽  
Scattering Measurements ◽  
The Relationship ◽  
Kinetics Of

ABSTRACTThe modelling of the aggregation kinetics of iron oxides has been succesful in predicting the increase in aggregate size as determined by dynamic light scattering measurements. The aggregates were found to exhibit fractal behaviour with fractal dimensions obtained from the scattering exponent in static light scattering studies dependent on the aggregation mechanism and ranging from 2.3 for rapid (diffusion limited) to 2.8 for slow (reaction limited) aggregation. Polydispersity and restructuring of aggregates were found not to affect the relationship between scattering exponent and aggregate fractal dimension. Excellent correspondence over a range of temperatures and ionic strengths has been obtained between results of sizing experiments using dynamic light scattering and sizes predicted using a modified Smoluchowski model incorporating fractal dimensions.

Universality of fractal aggregates as probed by light scattering

1989 ◽  
Vol 423 (1864) ◽  
pp. 71-87 ◽  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Master Curve ◽  
Rotational Diffusion ◽  
Fractal Dimensions ◽  
Scattering Data ◽  
Diffusion Limited ◽  
Single Master Curve ◽  
Using Data ◽  
Dynamic Light Scattering Data

Fractal colloid aggregates are studied with both static and dynamic light scattering. The dynamic light scattering data are scaled onto a single master curve, whose shape is sensitive to the structure of the aggregates and their mass distribution. By using the structure factor determined from computer-simulated aggregates, and including the effects of rotational diffusion, we predict the shape of the master curve for different cluster distributions. Excellent agreement is found between our predictions and the data for the two limiting régimes, diffusion-limited and reaction-limited colloid aggregation. Furthermore, using data from several completely different colloids, we find that the shapes of the master curves are identical for each régime. In addition, the cluster fractal dimensions and the aggregation kinetics are identical in each régime. This provides convincing experimental evidence of the universality of these two régimes of colloid aggregation.

Aggregation kinetics of OX50 hydrosols in NaCl solutions studied by dynamic light scattering

2016 ◽  
Vol 78 (5) ◽  
pp. 623-632 ◽  
Author(s):  
L. M. Molodkina ◽  
E. V. Golikova ◽  
R. S. Bareeva ◽  
A. N. Chusov ◽  
N. F. Bogdanova
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Aggregation Kinetics ◽  
Kinetics Of

Modelling of aggregation kinetics of colloidal systems and its validation by light scattering measurements

2004 ◽  
Vol 59 (8-9) ◽  
pp. 1783-1798 ◽  
Author(s):  
Marco Lattuada ◽  
Hua Wu ◽  
Peter Sandkühler ◽  
Jan Sefcik ◽  
Massimo Morbidelli
Keyword(s):  
Light Scattering ◽  
Aggregation Kinetics ◽  
Colloidal Systems ◽  
Scattering Measurements ◽  
Kinetics Of

Light-scattering studies of aggregation

1989 ◽  
Vol 423 (1864) ◽  
pp. 89-102 ◽  
Keyword(s):  
Fractal Dimension ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Power Law ◽  
Fractal Geometry ◽  
Linear Growth ◽  
Fractal Dimensions ◽  
Power Law Model ◽  
Aggregate Distribution ◽  
Scattering Measurements

We discuss dynamic and static light-scattering measurements made during slow (reaction-limited) aggregation of model colloids and immune complex forming proteins. Analysis of the results leads to an understanding of the random aggregates formed in terms of a fractal geometry and measurement of the fractal dimension. Differences in the measured fractal dimensions of the model and protein systems are discussed. The aggregation appears to follow ‘Smoluchowski-like’ kinetics as measured by a near linear growth of the low-angle light scattering with time. However, the dynamic light-scattering results support a simple power-law model for the aggregate distribution and allow an estimate of this power law to be made.

Dynamic light scattering study of intrinsic colloids of tetravalent actinides

2009 ◽  
Vol 1193 ◽  
Author(s):  
Sumit Kumar ◽  
B.S. Tomar ◽  
V.K. Manchanda
Keyword(s):  
Light Scattering ◽  
Ionic Strength ◽  
Dynamic Light Scattering ◽  
Scattering Measurements ◽  
Scattering Technique ◽  
Kinetics Of Formation ◽  
Dynamic Light Scattering Technique ◽  
Scattering Study ◽  
Kinetics Of ◽  
Light Scattering Technique

AbstractKinetics of formation of intrinsic colloids by tetravelent metal ions, namely, Th(IV), Hf(IV) and Pu(IV) have been studied using the dynamic light scattering technique. The milli-molar solutions of Hf(IV) and Th(IV) were prepared at varying pH (2-4) and ionic strength (0-0.01 M) and the samples were subjected to dynamic light scattering measurements at regular intervals for few days. The results showed that the size of intrinsic colloids varies with pH and ionic strength. In the case of Pu(IV) the concentration of aqueous solutions was 4.5×10−5 M.

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