Rings and Associated Arrangements

Pileni and coworkers [571,572] prepared rings as well as hexagons of nanocrystals of Ag, Cu, Co, CdS, and Ag2S (see Fig. 3.6). The formation of these structures is attributed to Benard-Marangoni instabilities caused by convection currents in an evaporating thin film. The convection currents could lead 

Besides rings, spontaneous formation of nanoparticle strip patterns has been observed on dewetting a dilute film of polymer coated nanoparticles floating on a water surface [577]. Hybridization of branched DNA trimers and Au nanoparticle DNA conjugates have been employed to produce discrete self-assembled nanoparticle dendrimers [578]. Self-assembly of triangular and hexagonal CdS nanocrystals into complex structures such as rods and arrows has been observed [579]. Furthermore, self-assembly of CdSe nanoparticle-copolymer mixtures has been observed wherein the copolymers assemble into cylindrical domains that dictate the distribution of the nanoparticles [580]. 

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