I don't quite understand your question.

Do you want TiO2 nanoparticles not to clump?

Dear Doan-Quan Mai,

I want to know if anyone has experience if an increase in TiO2 concentration to e.g. 10, 20mg/ml is feasible?

And yes, if possible particles should be as less aggregated as possible.

Best regards,

Nicolaj

Nicolaj Bischoff

The system will not be stable in DI water alone. You need the optimum amount of (usually phosphate) stabilizer. You will digest your ultrasonic probe with 'The stock dispersion will be sonicated for 30 minutes at 40KHz' - measure the conductivity of your water, the Fe, Cr, and Ni content before and after such a regime and you may be shocked! Take a look at (registration needed):

May 28th, 2019 Dispersion and nanotechnology

https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W190528DispNanoMat

November 3rd, 2015 Adhesion and cohesion

https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W180725AdhesionCohesion

Thank you all for your answers.

I found this publication, which answered most of my questions, regarding dispersion medium, sonication time and long term stability.

https://pubmed.ncbi.nlm.nih.gov/31378762/

Best regards,

Nicolaj

Nicolaj Bischoff

I have major criticisms of the paper you indicate. TiO2 has a high density (4.2 g/cm3) and DLS is not an appropriate measurement technique as the settling material (> 1 or 2 microns) is not analyzed. Further time/duration and ultrasound intensity are not measures of the energy input into the sample - it is more complex than that: temperature, shape of container etc all play a role. For any ionic additive ('admixture') used as a stabilizer, then there is always an optimum amount - too much is as bad as too little. The effect of concentration of the additives is not explored.