Do you mean a surfactant as a capping agent during synthesis of the nanoparticles or for binding to nanoparticles after they have been synthesised?

If it is for capping during synthesis, the choice of surfactant will affect the size and shape of the nanoparticles.

Fatty amines, dialkyl dithiophosphates and polyethylene glycol can be used to cap copper nanopartciles. Each has its own particular effects and optimum conditions for working.

You search for key word: Metallosurfactants; you will get it. Kobayashi et al has done lot of work in this area!!!!!

Thank you Anand and Richard for your useful answers. GC