Effect of competing monomer-monomer and monomer-particle interactions on the assembly of copolymer grafted nanoparticles

Functionalizing nanoparticles with copolymer ligands is an attractive method to tailor the assembly of the nanoparticles. In this talk we present simulation results that show the effect of competing monomer-monomer and monomer-particle interactions on assembly of nanoparticles grafted with AB copolymers with diblock or alternating sequence. We vary strengths of like-monomer (A-A and/or B-B) attractive interactions in the presence of strong or negligible monomer A- particle (A-P) attraction or monomer B- particle (B-P) interaction. At a constant particle size and graft length, the competing interactions and copolymer sequence dictate the amount of inter-grafted particle monomer aggregation, inter- and intra-graft monomer aggregation within the same grafted particle. The resulting monomer aggregation on/near the particle surface imparts an effective patchiness to the particle. For e.g., in case of particles grafted with AB diblock copolymer (with A block closer to the surface) the presence of strong B-P and B-B attractions leads to smaller attractive patches that extend from the surface, and in turn lead to anistropic assembly, while presence of strong A-P and A-A attractions lead to larger attractive patches closer to the particle surface and in turn isotropic assembly.