First prepare core nanoparticles of hydrophilic polymer. And dispersed it in the solvent in which you are supposed to prepared hydrophobic polymer. Then add the monomer of hydrophobic part and follow the procedure as u have.(add oxidizer etc.)

As on nanoparticles is already there in solvent then other will form on the surface of it(heterogeneous nucleation). that will give core-shell. In situ polymerization of hydrophobic polymer on prepared hydrophilic nanoparticles.

Hi Hossain,

Please look at this reference:

"Amphiphilic particles with hydrophilic core/hydrophobic shell prepared via inverted emulsions"

They used inverted emulsion polymerization with poly acrylamide as a core and another hydrophobic polymer as the shell. Hope it helps for you.

http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1097-4628(19960919)61:12%3C2129::AID-APP11%3E3.0.CO;2-2/abstract

By simple radical polymerization, you can obtain in one step random or alternate copolymers. However, you can graft a chain on another polymer. This is well known concerning cellulose modifications by grafting of hydrophobic polymeric chains. I prepared core-shell polymeric particles by such a process. Size and properties depend on nature, molecular weight and structure of both polymers.

Article Design aspects of poly(alkylcyanoacrylate) nanoparticles for...

Dear all,

Thank you so much for your helpful answers.

Concerning your answer, Dear Mohd, I should say that this way is so complicated. I have worked on that. In most cases, finding a suitable stabilizer working well in both polar and non-polar media is hard. In fact, when the medium changes, the colloidal stability will greatly deteriorate.

Double (mini)emuslion can also be used. But, this method requires precise, elaborate, and complicated control over the the preparation of emulsion!

Once again, thank you very much for your help.

This is a difficult task as hydrophilic-hydrophobic core-shell particles dispersed in aqueous media are not thermodynamically favoured, and will eventually invert to hydrophobic-hydrophilic core-shell structures. Semicontinuous (emulsifier-free) emulsion polymerization with the sequential addition of core and shell monomers, at extremely low rates of addition, appears to be a practical technique for this application, however, precautions should be taken to eliminate secondary nucleation in the course of polymerization. The methodology should be based on arresting the initial structure formed during polymerization by choosing the right monomers and polymerization conditions.  Crosslinking of the core might be sufficient if hard shells such as MMA and St are used under the right polymerization conditions, but there is a possibility that Janus particles form due to phase separation. The shell crosslinking also might be sufficient, however, the morphology of the particles might not always match the order of monomer addition, as again there is a possibility of inversion inside particles during polymerization. Application of a middle monomer phase (onion type particles), with hydrophilicity-hydrophobicity between those of the core and shell, can reduce the driving force for the phase change and help the morphology be arrested before phase separation can occur. Finally, crosslinking of both the core and shell have a better chance of achieving this goal, but obviously this will only produce hard particles with different properties with those which might be sought.

There is another way possible, as already mentioned by L. Pham, which is to conduct the inverse emulsion polymerisation (in oil media), in which hydrophilic-hydrophobic core-shell morphology is thermodynamically favoured, to first produce hydrophilic seed particles, followed by the addition of the shell monomers. The technique might appear easy on the paper, but there are complications involved in selecting the oil media and polymerization conditions, and might not be applicable to the monomers of interest. In the same group, alternatively, inverse miniemulsion polymerization is also possible.

I have written a review on that particular topic (inorganic core-polymer shell) in which you will find many relevant references (see attached file). Hope it can help. There are other review articles accessible in my research gate portal.

Regards

Dear Prof. Sajjadi,

Thank you so much for your detailed answer and mentioning the important points about which I haven't even thought so far.

Your suggestions were really helpful and I'm so grateful to you.

Concerning the article that Dear. Pham mentioned. yes you're right. What the authors have synthesized is just coagulum as SEM images show !

Also, thank you so much for your answer, dear prof. Lami.