Greetings, Taiseer Mohamed Abd El-Daim Yes, definitely! it is interesting to note that the encapsulation of nanoparticles causes a decrease in polymer size, which has applications in nanotechnology and drug delivery. The final size of the encapsulated nanoparticles is determined by the interaction between drug-polymer compatibility, nanoprecipitation techniques, and polymer : drug ratio.

How are you determing the size of nanoparticle and polymer ? Is it DLS? Then it is the hydrodynamic radius. It is a possibility that the hydrodynamic radius is the one you are measuring after the encapusation. The polymric chains may be entangling/covering the nanoparticles and a result it's effective length decreasing as compared to it's free form. That will be manifested in DLS study.

Hi,

the accepted explanation is the conformational changes caused by the polymer adsorption on the nanoparticle surface. In short, the adsorption reduces enthalpy due to the attractive polymer-particle interaction, and these savings help overcome the entropic penalty related to the shape distortion. Another option is that some nanoparticles may change the electrochemistry of the solution (pH, zeta potential, screening length, etc.), tuning the internal interactions within the polyner chain. You may find more details in our papers:

https://www.researchgate.net/publication/345430349_Thermodynamic_Parameters_Controlling_Nanoparticle_Spatial_Packing_in_Polymer_Solutions

https://www.researchgate.net/publication/353308097_Phase_diagram_of_bare_particles_in_polymer_nanocomposites_Uniting_solution_and_melt_blending

https://www.researchgate.net/publication/323045457_Bulk_Polymer_Nanocomposites_with_Preparation_Protocol_Governed_Nanostructure_The_Origin_and_Properties_of_Aggregates_and_Polymer_Bound_Clusters

Don't forget to consider the peculiarities of the experimental techniques in question, such as the one mentioned by Partha Pratim Chowdhury. How did you obtain your data?