Surface functionalization of nanodiamond particles via atom transfer radical polymerization

Ultradispersed diamond (UDD)/polymer brushes having excellent solution dispersibilities are prepared by atom transfer radical polymerization (ATRP) using the “grafting-from” synthesis strategy. ATRP initiators, covalently attached to oxidized surface carbon atoms of UDD aggregates using esterification chemistry, initiate polymerization of methacrylate monomers to form hydrophobic UDD/poly(iso-butyl methacrylate) and UDD/poly(tert-butyl methacrylate) polymer brushes. Acid hydrolysis of a UDD/poly(tert-butyl methacrylate) polymer brush affords a hydrophilic UDD/poly(methacrylic acid) polymer brush. Based on surface area measurements and GPC data, the calculated surface density of a representative UDD/polymer brush material is ca. five polymer chains/100 nm2. A wide variety of UDD/polymer brush materials having controlled dispersibility and functional group reactivity are now potentially available using this synthesis strategy.