Polystyrene block copolymers, gold colloid

Adsorption of block copolymers onto a surface is another pathway for surface functionalization. Block copolymers in solution of selective solvent afford the possibility to both self-assemble and adsorb onto a surface. The adsorption behavior is governed mostly by the interaction between the polymers and the solvent, but also by the size and the conformation of the polymer chains and by the interfacial contact energy of the polymer chains with the substrate [115-119], Indeed, in a selective solvent, one of the blocks is in a good solvent it swells and does not adsorb to the surface while the other block, which is in a poor solvent, will adsorb strongly to the surface to minimize its contact with the solvent. There have been a considerable number of studies dedicated to the adsorption of block copolymers to flat or curved surfaces, including adsorption of poly(/cr/-butylstyrcnc)-ft/od -sodium poly(styrenesulfonate) onto silica surfaces [120], polystyrene-Woc -poly(acrylic acid) onto weak polyelectrolyte multilayer surfaces [121], polyethylene-Wocfc-poly(ethylene oxide) on alkanethiol-patterned gold surfaces [122], or poly(ethylene oxide)-Woc -poly(lactide) onto colloidal polystyrene particles [123],... 

Although polyethyleneoxide is a bad stabilizer for colloidal noble metals, it appeared possible to prepare rather stable colloidal gold solutions in toluene with polystyrene/polyethyleneoxide block copolymers by reduction of LiAuCU. When polymer/salt complexes were allowed to approach their equilibrium during longer times, a more homogeneous distribution of gold salt in the micelles resulted in more narrow particle size distributions. 

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