Dear Chandan Kumar,

maybe it's due the molecular chain breaking in polymer structure and making a new impurities.

Regards

due the breaking up of longer molecular chains of polymer and proper sonication may not done.

what is size of the particle gives some idea about the  solution

Dear Rao Sir,

After depositing the solution on glass, by eye only it was visible that few bigger particle was there. When I was discuss with few polymer researcher, they told, "Don't do ultrasonication with polymer". But many authors have reported ultrasonication of polymer in their papers. What are the advantages of ultrasonication with polymer??

Dear chandan kumar

i hope the following websites may be useful to u

http://www.journals.elsevier.com/carbohydrate-polymers/recent-articles/

https://www.researchgate.net/profile/Jiandong_Ye/publication/225810808_Deagglomeration_of_HA_during_the_precipitation_synthesis/links/53d99b7a0cf2a19eee880237.pdf

Article Deagglomeration of HA during the precipitation synthesis

Most probably it happens due to chain-breakage into radicals - with further recombination - which results in crosslinking, swelling of the network formed -- and as a final result -----> gel-formation

Regards,        Leonid

I agree with  Leonid. In ultrasonic bath the bubbles of various sizes break together and the temperature at the tiny region can go as high as 5000K. This is the reason for chain breaking/bond breaking and production of radicals which can react together to make crosslink and become insoluble. You get particles separating at the bottom.

Dear \ Chandan Kumar

The using of ultrasonication on the preparation of polymer have several advantages depending on the nature of solvent ,the temp. and the time exposure.