Ultrafast Self-Assembly Using Ultrasound: A Facile Route to the Rapid Fabrication of Well-Ordered Dense Arrays of Inorganic Nanostructures

摘要

The use of self-assembly for generating ordered ensembles of functional nanostructures at surfaces has seen significant progress in the last decade owing to the simplicity and low-cost of the process. In particular, block copolymers (BCP) comprising chemically distinct blocks that can phase-separate into nanoscaled domains owing to mutual incompatibility between the blocks have extensively been exploited for self-assembly. In case of poly(styrene)-black-poly(vinyl pyridine) (PS-b-PVP), by using an apolar solvent such as toluene, the BCP self-assembles into spherical reverse micelles with PVP and PS forming the core and the corona, respectively. When such micelles are loaded with inorganic precursor salts and then transferred onto substrates by dip coating or spin coating, they spontaneously arrange themselves into 2D arrays. By subsequent plasma treatments, inorganic nanodot arrays can be achieved thereby preserving the original arrangement of the micellar ensembles. The flexibility to control both the particle size and the interparticle spacing has enabled intensive studies in different fields including optics, optoelectronics, magnetic recording media, catalysis, chemical reactivity, nanotubes and nano-wires, and biomedicine. Furthermore, micellar ensembles were successfully utilized as masks to nanopattern surfaces.