Surfactant-mediated self-assembly of Au nanoparticles and their related conversion to complex mesoporous structures.

In this work, we report a hydrothermal method for self-assembly and organization of as-synthesized gold nanoparticles into various aggregative morphologies. Using the assembled gold nanoparticles as structural precursors, furthermore, mesoporous gold spheres in either discrete or interconnected form can be prepared at higher process temperatures through removal of bidentate organic linker molecules. Excellent product controllability and high morphological yield have been achieved via tuning preparative parameters. Our preliminary investigations also show that the assembled gold nanoparticles and nanostructures can be used as building blocks for construction of three-dimensional networks as well as for fabrication of two-dimensional porous thin films. The present work confirms our earlier prediction that Ostwald ripening may also be operative for pre-organized organic capped nanocrystallites in producing hollow structures.