You do not need to determine the optimal immersion depth of the disperser rod. You need to determine the optimal nanoparticle size distribution after the dispersion that you need.

I think there is no need to optimize the length. Just take care that the probe should not touch the bottom surface or the walls of the reaction flask.

Thanks AS sir & Prof. YM sir for insight

Sir

Yuri Mirgorod,

what could be possible way to dispersed nano particle so that shape remain unchanged?

Dear Bhaskar Bhatt,

The shape of synthesized nano particles is not affected by sonication but size is affected by sonication because it disperse the nano particles which also prevent agglomeration. The suspension of nano particles is dispersed in ultrasonicator under normal condition.

Thanks @ JS

sir size only i want to know? 20 nm will get 20 nm or not ?

@Bhaskar Bhatt.

To obtain the desired shape of nanoparticles, you must precisely fulfill all the conditions for their synthesis. Shape control of nanocrystals is achieved by accurately tuning the nucleation and growth processes, which may be under both thermodynamic and kinetic control. May be seed-mediated , template-assisted, control of growth kinetic, surfactant-directed, supramolecular-directed, complex-template... synthesis.

I guess if the nanoparticles are small enough, with no aggregation, their size and shape would not change on sonication. I think the change in size and shape are highly dependent on the forces by which the nanoparticles attached to each other.

It depends to the time that they remain in aqueous solution after synthezising ! I believe that you can do it for less than 6 months.

Soheil Fatahian what is 6 Months?

By definition, sonication disrupts agglomerates and not aggregates. Take a look at (open in Internet Explorer) these webinars:

• Ultrasound, cavitation, and the singing kettle http://tinyurl.com/olueohz
• Adhesion and cohesion http://tinyurl.com/zwb2wlh
• Dispersion and nanotechnology http://tinyurl.com/hpywsge (Opens in Internet Explorer only)

Particle is the smallest entity which cant be separated further by the application of ultrasonic energy. Hence we can expect the shape and size to remain the same.

Alan F Rawle sir, Thanks

first of all, result may depend on actual chemical composition. E.g. nanotubes or even needle like crystals may break. If there are several crystal modifications, provided sufficient solubility, theoretically there might be also a transformation from one to another modification. Take nothing for granted. Do the experiment.

Titus Sobisch sir, thanks & for synchronous answer

Bhaskar Bhatt I agree with @Titus, you have to study your case. You also need to have in consideration both time and sonication potency. Keep in mind that in synthesis of some polymeric nanoparticles, final size obtained depend on these factors.

I agree with Dr Alan F Rawle .