Zeta potential measurements for non-spherical colloidal particles – Practical issues of characterisation of interfacial properties of nanoparticles

The optimisation of new particle based products with respect to their stability and physico-chemical behaviour requires the characterisation of the interfacial properties. Such a characterisation may be achieved by means of the zeta potential, which is related to the surface charge and electric double layer (EDL) of colloidal particles. Furthermore, the zeta potential is a powerful parameter of the EDL and an appropriate way of predicting the suspension stability. This study discusses the performance of two techniques for the measurement of zeta potential value and its comparability of zeta potential values for pyrogenic materials. This measurement encounters several experimental challenges, because each measurement technique possesses specific limits with regard to particle size, concentration and morphology. Furthermore, this study examines the comparability of zeta potential measurements by variation of mentioned specific limits taking the conservation of the chemical equilibrium into account and also understanding the impact of aggregate morphology on the electrokinetic mobility.