Dear Rohit

For polymeric nanoparticle synthesis, there are different ways to synthesize them. though, i guess it would be good to synthesize them via reverse emulsion method.you will find many protocol using reverse emulsion method.

regards

By chemical reduction methods using cross linked  hydro gels with multi functional hydrophylic functional groups.

 Dear Raju Sir

can't there be any physical methods to deal with the problem of size control synthesis 

There is one method by using ball mill method.

a number of techniqeus can be used to synthesized polymer nanoparticles. Among them, self-assembly is popular due to being simple, easy and fast. Self-assembly polymer nanoparticles generally have size larger than 40 nm. For polymer nanoparticles less than 10 nm, you may consider disassembly strategy that we developed recently. If interested, pls find more detailed information in our Polymer Chemistry papers.