Control of Synthesis and Structural Analysis of Poly(glycerol) Functionalized Nanodiamonds

Poly(glycerol) (PG) functionalization is one of the most common surface functionalization methods for a variety of nanoparticles (NPs). The hyperbranched hydrophilic polymer on NP surface gives advantageous features; dispersibility in aqueous media with high ionic concentration and extensibility for further functionalization through abundant -OH group. In addition, PG layer suppresses the adsorption of serum proteins in physiological environment to evade immune response or other non-specific interactions.<br/>For PG functionalized nanodiamonds (ND-PG), to enable material and process design more quantitatively, we conducted the analyses of PG functionalization reaction, in which ring opening polymerization of glycidol (GD) on ND surface is done in ethylene glycol (EG) as a solvent, and structure of ND-PGs. As a result, we found that the amount of PG can be precisely controlled by the reaction conditions, use amount of GD and EG, and properties of ND core, oxygen content and particle size. In the structural analysis, the abundance ratios of substructures of glycerol unit in PG chain and the thicknesses of PG layer in dispersion for ND-PGs of different PG amounts and ND cores were elucidated by NMR, TGA and DLS.<br/><br/>M. Nishikawa et al, <i>Carbon</i> <b>2023</b>, <i>205</i>, 463–474.