Measurements of Streaming Potential for Mica Covered by Colloid Particles

Abstract

The zeta potentials of natural mica, bare and covered by positively charged latex particles of micrometer size range, were determined by the streaming potential method. Measurements were carried out using the parallel-plate channel formed by clamping together two mica sheets separated by a Teflon spacer. The dependence of streaming potential on surface coverage (ϑ) of adsorbed particles was determined for various ionic strengths and particle sizes. The coverage was determined directly by optical and electron microscope counting procedures. It was found that the negative streaming potential for bare mica E s was significantly increased by the presence of adsorbed particles. The dependence of the reduced streaming potential E s p /E s (where E s p is the zeta potential in the presence of particles) on ϑ exhibited an universal behavior being independent of particle size and ionic strength. These experimental data were interpreted in terms of a theoretical model postulating that the streaming potential change was due to flow damping over the interface and by charge transport from the double-layer surrounding adsorbed particles. In contrast with previous approaches no assumption of the slip (shear) plane shift upon particle adsorption was made. By exploiting the experimental results it was suggested that colloid and bioparticle adsorption kinetics can be studied in situ using the streaming potential method.

Irreversible adsorption of latex particles on fibrinogen covered mica

“…Streaming potential measurements were carried out using a home-made apparatus described in details previously (Adamczyk et al , 2007Zembala and Adamczyk 2000). The main part of the cell was the parallel plate channel of dimensions 2b c × 2c c × L equal to 0.027 × 0.29 × 6.2 cm formed by mica sheets separated by a perfluoroethylene spacer.…”

“…In this way the cell electric resistance R c was determined to incorporate the surface conductivity effect affecting streaming potential in solutions of lower ionic strength. Correction for surface conductivity was introduced according to the procedure described elsewhere Zembala and Adamczyk 2000). It is worthwhile mentioning, that this correction was negligible for the ionic strength of the electrolyte above 10 −3 M.…”

“…Latex article deposition proceeded over a desired time (typically 24 hours). The true coverage of particles was determined by a direct optical microscope counting under wet conditions, as described in our previous works (Adamczyk et al , 2007Zembala and Adamczyk 2000;Zembala et al 2003). Particles were counted over 10-20 equal sized areas chosen randomly over the mica sheet.…”

“…Such electrokinetic experiments have been carried out using parallel plate channel cells devised originally by van Wagenen and Andrade (1980) and then used to widely to determine electrokinetic characteristics of bare surfaces (mica, silica slides) (Scales et al 1990(Scales et al , 1992, colloid particles Zembala and Adamczyk 2000;Hayes et al 1999;Zembala et al 2003) or protein covered surfaces (Norde and Rouwendal 1990;Elgersma et al 1992;Vasina and Dejardin 2004;Etheve and Dejardin 2002). However, a disadvantage of the streaming potential measurements is a tedious assembling prior to experiment, sealing problems and the necessity of determining the correction due to surface conductance of the cell.…”

Adsorption monitoring of phospho-l-serine on hydroxyapatite

“…The kinetics of adsorption is very important as the time scale of adsorption is very decisive for materials performance and it may vary depending on molecular properties and on the nature of the adsorbent. Streaming potential (SP) measurements have been suggested as a potentially useful tool to monitor the adsorption from solution [20][21][22][23][24][25][26]. SP in combination with the electrical conductivity measurements allows for the evaluation of ζ-potential taking into account the surface conduction phenomenon, which affects significantly the calculated ζ-potential values [27,28].…”