Measurement of the zeta-potential of solid surfaces through Laser Doppler Electrophoresis of colloid tracer in a dip-cell: Survey of the effect of ionic strength, pH, tracer chemical nature and size

Measurement techniques for detecting surface charge have gained attention in the last few decades due to the importance of this parameter in many scientific and industrial applications. The estimation of macroscopic surface zeta-potential (ζ) is customarily performed via streaming potential measurements. Recently, a simple and cost-effective Malvern Zetasizer accessory has been introduced which makes use of electroosmotic flow mapping (EOFM) to determine surface charge of hard surfaces. In this work we propose a measurement strategy that considers the key parameters influencing the reliability of surface ζ values. With this purpose, the role of the ionic strength, sample cleaning, tracer particle size and chemical nature on the determination of ζ for borosilicate glass coverslips have been investigated. ζ values obtained in presence of adjusted parameters was finally compared to the equivalent results of streaming potential technique, validating the proposed measurement strategy.