Polymer-grafted nanoparticles (PGNs) with adjustable graft-density and inter-particle hydrogen bonding interaction

Polymer-grafted nanoparticles (PGNs) receive enormous attention because they possess the advantages of both the grafted polymer and inorganic cores, and thus may demonstrate superior optical, electronic, and mechanical properties. One potential application is PGN arrays for making optical or magnetic structures, where the tailorable interparticle interactions are significant for the formation of superlattice structures with a defined and ordered arrangement. In this work, we report the synthesis of PGNs which can form interparticle hydrogen-bonding to enhance the formation of well-defined 2D nanoparticle arrays. Various polymers, including poly(4-vinyl pyridine) (P4VP), poly(dimethyl aminoethyl acrylate) (PDMAEMA), and poly(4-acetoxy styrene) (PAcS), are attached to silica cores by a “grown from” in a mini emulsion-like synthesis approach. SiO₂-PAcS brushes are deprotected by hydrazinolysis and converted into poly(4-vinyl phenol) (PVP), containing hydroxyl groups as potential hydrogen-bonding donor sites. Understanding and controlling interparticle interactions by varying grafting density, and formation of interparticle hydrogen bonding relevant for self-assembly of PGNs and formation of PGN superlattices structures are the motivation for this study.