I saw that under microwaves synthesis, silver nanoparticles evolutes to flower like shape, but in general the modulation of pH control the shape well. In my case I got a star-like shape with bacterial assistance synthesis. the power of reducing agent apply a force to manage the size especially. Finally there are many factors that influence the shape and size and each phase react particularly to these factors.

Hi Ali Sdiri,

I beleive it is simply a question of hazard and there is no a specific rule that allows the prediction of nanomaterials shape, except in the cases of nanomaterials growth-up from atoms using for example the atom-by-atom assembly.

I think you can obtain high homogeneous flower shape by chemical vapor deposition

If is chemical synthesis from solution, the ion concentration of the precursors, the ionic strength, pH, temperature, and specially additives, all define the size and morphology of nanoparticles. I have seen flower-shaped nanoparticles made of Au that have also been very useful for plasmonic applications such as surface-enhanced Raman.