Yuan, J.; Wunder, S.; Warmuth, F.; Lu, Y.: Spherical polymer brushes with vinylimidazolium-type poly(ionic liquid) chains as support for metallic nanoparticles. Polymer 53 (2012), p. 43-49
We present here the synthesis of spherical polyelectrolyte brushes by photo-emulsion polymerization with a solid polystyrene core (diameter ~ 100 nm) onto which chains of vinylimidazolium-type poly(ionic liquid)s have been densely grafted. The as-synthesized brush particles were employed as nanoreactors for the generation and immobilization of metal nanoparticles. Transmission electron microscopy characterization shows that Au and Pd nanoparticles with diameter of 2.1 nm and 2.5 nm are homogeneously embedded inside the PIL brushes, respectively. The study of swelling behavior of the brush particles before and after metal deposition indicates obviously ion-specific effect. The composite particles exhibit a long-term colloidal stability in aqueous solutions as well as in ionic liquids. Catalytic activity of the as-synthesized metal nanocomposite particles is investigated by using the reduction of 4-nitrophenol with NaBH4 as a model reaction, which can be compared directly with reported systems. In addition, it is found that the rate constant kapp of PIL-metal nanocatalyst could be modulated by salt concentration.