Preparation of platinum nanoparticles using star-block copolymer with a carboxylic core

Well-defined star polymers containing a functionalized core supply a molecular nanocavity and may be used to control formation of inorganic nanoparticles. Herein, platinum (Pt) nanoparticles of 2–4 nm were prepared by using (poly(acrylic acid)-b-polystyrene)6 (PAA-b-PS)6 amphiphilic star block copolymer as a novel single molecular stabilizer. This PAA core functionalized star polymer was obtained by hydrolysis of (poly(tert-butyl acrylate)-b-polystyrene)6 (PtBA-b-PS)6, which was synthesized by sequential atom transfer radical polymerization (ATRP) of tert-butyl acrylate and styrene with an initiator bearing six 2-bromoisobutyloxyl groups. Pt(IV) ions were loaded by ion exchange to the core of the star polymer and Pt nanoparticle stabilized by single star polymer was produced by a reduction with NaBH4.