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How fast do your particles move?

25 October 2011 No Comment

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The recent bombshell story that some particles may be able to travel faster than light is fascinating. However, my thoughts are generally on particles that are larger than neutrinos – and how fast they move within a colloid. Not even approaching the speed of light, this velocity is dependent upon the zeta potential of participating particles.

What is zeta potential?

By applying an electric field across a dispersion, the velocity of the migration of charged particles towards the oppositely charged electrode can be measured. This measurement will be proportional to the magnitude of the zeta potential. As zeta potential is one of the main forces to mediate interparticle interactions, it acts as an indicator of the stability of colloidal systems.

Easy surface zeta potential measurements

A new surface zeta potential measurement cell accessory for Malvern’s Zetasizer Nano allows users to measure the zeta potential of surfaces in an aqueous medium. As a simple accessory for a standard instrument, the cell neatly eliminates any need to use streaming potential – a specialist technique which requires dedicated instrumentation.

While it seems fairly straightforward to see the benefits to purchasing a single cell accessory over an entire, dedicated system, if you ever feel the need to compare the new method with the old, I refer you to a paper by Elimelech et al.

An introduction to the new surface zeta potential measurement cell

On 4 October 2011 we hosted a webinar that discussed ‘Measuring the zeta-potential of planar surfaces’, which gave an excellent overview on how this technique can be used to quantify the properties and predict the behaviour of suspensions and colloids. The presentation is now freely available online as part of Malvern’s extensive collection of on-demand web seminars..

If you find yourself with further questions, please don’t hesitate to ask!