Substrate Based 'Bricks-and-Mortar' Self-Assembly of Spherical Nanoparticle Aggregates

摘要

Transmission Electron Microscope (TEM) sample girds were coated with recognition element functionalized polymer 2 and exposed to solutions of a Mixed Monolayer Protected Gold Cluster (MMPC) functionalized with a complimentarily recognition element. Interactions between the polymer and MMPC bound recognition elements provide a driving force for the formation of nanoparticle aggregates. Characterization of the resulting structures by TEM revealed that anisotropic growth of structures in the sub-micrometer size regime rapidly occurred. This process was shown to be the result of the specific hydrogen-bonding interactions between the two components. Casting films of polymer 2 from solutions of decreasing concentration achieved control over the process. This led to the increased formation of regular, circular structures and a decrease in random nanoparticle adsorption by the film. Analysis of the size of the circular structures revealed that a maximum diameter of approximately 1150 nm was achieved after 30 minutes exposure to MMPC 1 solutions. This size was independent of the concentration of polymer 2 solutions used to cast films.