Micellar soft-templates

Figure 17.3 Micellar soft-templates for self-assembling conducting polymer nanostructures via a...

Mesophase structures self-assembled from surfactants (Figure 8.35) provide another class of useful and versatile templates for generating ID nanostructures in relatively large quantities. It is well known that at critical micellar concentration (CMC) surfactant molecules spontaneously organize into rod-shaped micelles [315c]. These anisotropic structures can be used immediately as soft templates to promote the formation of nanorods when coupled with appropriate chemical or electrochemical reaction. The surfactant needs to be selectively removed to collect the nanorods/nanowires as a relatively pure sample. Based on this principle, nanowires of CuS, CuSe, CdS, CdSe, ZnS and ZnSe have been grown selectively by using surfactants such as Na-AOT or Triton X of known concentrations [238, 246]. 

Sodium bis(2-ethylhejQ l) sulfosuccinate (AOT), which can solubilize a relatively large amount of water [116], was selected as the sulfactant for the reverse microemulsion system. An aqueous FeCIa solution was added into an AOT/ apolar solvent mixture at room temperature. Subsequently, cylindrical reverse micelles, soft templates for the fabrication of nanotubular structures, were generated [117]. AOT micelles are generally a few nanometers in size in the absence of water. However, the addition of water dramatically increases the average aggregation number of the reverse micelles and thus the hydrod mamic radius of the aqueous micellar core increases [118]. 

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