Colloidal properties magnetic particles

Particularly attractive for numerous bioanalytical applications are colloidal metal (e.g., gold) and semiconductor quantum dot nanoparticles. The conductivity and catalytic properties of such systems have been employed for developing electrochemical gas sensors, electrochemical sensors based on molecular- or polymer-functionalized nanoparticle sensing interfaces, and for the construction of different biosensors including enzyme-based electrodes, immunosensors, and DNA sensors. Advances in the application of molecular and biomolecular functionalized metal, semiconductor, and magnetic particles for electroanalytical and bio-electroanalytical applications have been reviewed by Katz et al. [142]. 

The dimensions, shape, aspect ratio, and other morphology characteristics influence the macroscopic properties of the materials. The microstmcture of particles is frequently used to explain the viscoelastic, electric, magnetic, and optical properties. In the field of composites, microscopy is essential to measure the shape and size of particle filler inside of the polymer, but it is important to determine particle distribution, segregation, and characteristics of the interface, hi the field of colloidal polymers, the properties of particles can be studied to explain the stability, rheology, color, and coalescence. The main techniques used to characterize the microscopic stracture of polymers are scanning electron miaoscopy (SEM), TEM, scanning probe microscopy (SPM), and their related techniques. 

The curve follows the fit of the model describing the size dependence. The three experimental points match the curve quite well and we can now understand why even 15 nm palladium colloids show magnetic behavior still far from that of the bulk. Even for a 1 micron sample, one can expect a reduction in x of about 1 % Values for A and X obtained from different experiments for similarly sized particles agree quite well with the results discussed here. [61-64] Finally, we see that the magnetic properties of ligand stabilized particles, even if they are very huge particles like colloids, differ considerably from those found in the bulk. The... 

M. Ozaki, Magnetic particles Preparation, properties, and applications, in Surface and Colloid Science (E. Matijevic and M. Borkovec, eds.), vol. 17 of Surface and Colloid Science, pp. 1 26, Springer US, 2004. 

Pastor-Satorras R, Rubi R (1998) Fractal properties of cluster of colloidal magnetic particles. Prog Colloid Polym Sci 110 29-33... 

The second part covers the structural aspects of different colloidal systems. Chapters 3 and 4, by Martin-Molina et al. and Haro-Pdrez et al., deal with electric double layers and effective interactions. Chapters 5 and 6, by Delgado et al. and Martinez-Pedrero et al., explore the structure of extremely bimodal suspensions and fllaments made up of miaosized magnetic particles. Chapters 7 and 8, by Puertas and Fuchs, and Hynninen et al., analyze the role played by the attractive interactions, confinement, and external fields on the structure of colloidal systems. Chapters 9 and 10, by Tromp and Maldonado-Valderrama et al., cover some structural aspects in food emulsions. This second part of the book finishes with Chapter 11, by de Vicente, which analyzes the rheological properties of structured fluids in order to establish a connection between measured material rheological functions and structural properties. 

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