Colloidal particles impedance

T. Sun, C. Bemabini and H. Morgan, Single-colloidal particle impedance spectroscopy complete equivalent circuit analysis of polyelectrolyte microcapsules, Langmuir, DOT 10.1021/la903609u (2009). 

Chronopotentiometry, galvanostatic transients, 1411 as analytical technique, 1411 activation overpotential, 1411 Clavilier, and single crystals, 1095 Cluster formation energy of, 1304 and Frumkin isotherm, 1197 Cobalt-nickel plating, 1375 Cold combustion, definition, 1041 Cole-Cole plot, impedance, 1129, 1135 Colloidal particles, 880, 882 and differential capacity, 880 Complex impedance, 1135 Computer simulation, 1160 of adsorption processes, 965 and overall reaction, 1259 and rate determining step, 1260... 

Impedance is the ratio of the voltage across a system to the current passing through the system. It measures the dielectric properties (permittivity and conductivity) of the system. The dielectric behavior of colloidal particles in suspension is generally described by Maxwell s mixture theory [26]. This relates the complex permittivity of the suspension to the complex permittivity of the particle, the suspending medium and the volume fraction. Based-on Maxwell s mixture theory, shelled-models have been widely used to model the dielectric properties of particles in suspension [35-40]. A single shelled spherical model is shown in Fig. la. 

SO as to eventually seriously impede the elution process. In practice, a larger volume of eluate is present after precipitation and re-acidiiication then is necessary for the next elution cycle. Consequently, this provides the opportunity for a purge of sulphate ion by discarding a proportion of the liquor each cycle. The discarded eluate must not carry away with it an undue amount of uranium, e.g. in a finely divided colloidal condition hence the necessity to have good filtration, at least for that portion which is discarded. The complete removal of uranium is less important for the main part of the eluate which is recycled, since any insoluble uranium particles tend to dissolve again in acid and be added to the next cycle. 

The use of colloidal silica has been investigated as well. Kozlowski et al. (1992) have used colloidal silica to form a protective coating on calcareous stones. Silica particles were deposed within the pores ofthe stone. The passage ofwater through the pores was impeded by the presence of the particles. The results of field trials have not yet been reported. 

Colloidal silica from various origins or chalk or other fine-particle fillers are normally added. If the particles of antiblocking agent incorporated are too large, they can impede surface sliding. This effect is used for antislip modification. The products used here are high molecular weight thermoplastics or elastomers [33] predispersed in a suitable carrier, they form evenly distributed particles on the film surface [34]. 

De Oliveira HP, Andrade CAS, de Melo CP (2008) Electrical impedance spectroscopy investigation of surfactant-magnetite-polypyrrole particles. J Colloid Interface Sci 319 441 49... 

---