I have used refractive index of 1.96. And distilled water as the dispersion liquid. And a zeta dip cell is used. Each time the value of zeta potential is showing zero irrespective of pH. Also, the absorption value is set to zero. Even at absorption value of 1, zeta potential is zero.
Are you asking which liquid to use to disperse the particles or which liquid to tell the instrument you are using? If you change the liquid itself then the zeta potential will most likely change. If you are simply changing the software setting, the zeta potential will be calculated incorrectly if the viscosity is different.
For zeta potential, it's the refractive index of the liquid that is needed. The optical properties of the solid are not.
When you say the zeta potential is zero, do you really mean zero (0.000) or that it is small?
Please share an example report from the instrument including graphs.
John Francis Miller Thank you John for the follow-up.
The graphene oxide is prepared in distilled water. And then at different pH value of 3, 7, 10, 13 the zeta potential is showing 0.08 mV and a standard deviation of 2.1 mV.
I used the refractive index of graphite solid as 1.96, but as you said it is the refractive index of liquid which matter. So, I will use a value of 1.33.
So, do you think changing the refractive index value to 1.33 will work under different pH and value (zeta potential) will show some contrast and at least not a value close to zero every time?
Changing the refractive index will just scale the calculated zeta potential accordingly. It's an optical parameter related to the geometry of the instrument.
Have you checked your instrument with a zeta potential standard to make sure it is okay? Maybe the electrodes are faulty.
An example report will be very helpful. There are many questions it can answer to help identify what might be happening. I'm happy to take a look.
(If you are interested, I am hosting a free webinar on 19 March 2019 regarding zeta potential measurement: http://eepurl.com/ghqsp9 )
John Francis Miller Thank you John for the follow-up again. I will report to you the details you asked very soon.
Meanwhile will register for the webinar. Thank you so much.
John Francis Miller Hi John...I registered for the webinar. So how we can join it on 19th March ? Will there be a link that will be shared before the webinar commencement ?
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