Hi Tanushree,

Two routes are possible:

1. Make the water less hydrophilic

2. Make the solid more hydrophilic

For 1. you could (if that is allowed for your system) add alcohols (e.g. 20 (vol/vol)% ethanol) or other solvents with low surface tension. At 20 (vol/vol)% ethanol in water, the solution has a surface tension still close to that of pure alcohol. This will greatly enhance wetting of your particles, whether it will also stabilize them longer term, I am not sure?

For 2. you could use a polyelectrolyte that absorbs onto your solid and gives it charge thus making it better dispersible. I have often used Styrene Maleic anhydride, neutralized with NaOH, like SMA1000 from Cray Valley. There are also other polyelectrolytes, like Calgon-types (polyphosphates). This approach should also stabilize the particles.

I hope this helps, kind regards, Leo 

Dear Dr. Leo,

Thank you very much for your detailed and helpful answer. It would be more helpful for me if you kindly suggest me any article regarding this.

Thanks again.

Kind Regards,

Tanushree

Hi Tanushree,

It is difficult to find general articles on this. However, I did find a presentation by Horiba which describes how to disperse powders for particle size analysis:

http://www.horiba.com/fileadmin/uploads/Scientific/Documents/PSA/Webinar_Slides/TR016.pdf

If you need a good book on this topic I can recommend Prof. Tadros's book:

Tadros, Tharwat F., ed. Dispersion of powders in liquids and stabilization of suspensions. John Wiley & Sons, 2012.

It is a popular book so should not be difficult to find. You can also search the book and download chapters via this link: http://onlinelibrary.wiley.com/book/10.1002/9783527656592

Kind regards, Leo

Dear Dr. Leo,

Thank you very much for your kind suggestion and cordial cooperation.

Kind Regards,

Tanushree Halder

You could do it by reducing the polarity of water by adding a less polar but miscible solvent to water. Alcohols are a good choice. You could also try other solvents.

Try sonication if you are interested in making a suspension.

Methods like UV irradiation, ozone treatment can help sometimes, they increase the hydrophilicity of your material but there is a risk of chemical changes to your material. You could try these methods if they suit your application.