The self-assembly of coated gold nanoparticles at the water/vapor interfaces are studied using explicit-atom molecular dynamic simulations.  While it is often assumed that uniformly coating spherical nanoparticles with short organic lead to symmetric nanoparticles, we find that the high curvature of small nanoparticle and the relatively short dimensions of the coatings can produce highly asymmetric coating arrangements. At an interface this asymmetry of the ligands tends to orient the nanoparticles with the surface so as to minimize free energy. First results for individual gold nanoparticles of diameter 2-8 nm coated with alkanethiol ligands of various lengths and different end group will be presented.  Results for the self-assembly of the multiple nanoparticles at the water/vapor interfaces will then be presented for the diameter 2 and 4 nm nanoparticles which show how these asymmetric and oriented coatings effect the interactions between nanoparticles and the structure of the resulting aggregate.

Self-assembly of gold nanoparticles at the water/vapor interface

243rd National Meeting (2012)

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