Interface Colloidal Deposition of Nanoparticle Wire Structures

Abstract

Development of fabrication methods for nanoparticle structures, such as dielectrophoresis [3] and lithography, is an active area of research. Existing lithography methods can either directly assemble nanoparticles in the shape of arrays [4] or provide a platform for nanoparticle assembly. [5] Ordered arrangements of nanoparticles on templates such as block copolymer scaffolds [6] and crystal step edges [7] have also been explored. Efforts to assemble nanoparticles onto substrates via molecular linkers in patterned [8] and unpatterned [9] geometries have also been reported. Single-step assembly methods like dielectrophoresis are attractive; [10] however, users may have limited control of the resulting structures and must take care to tune the dielectric contrast between particles and solvents in order to achieve optimal results. These and other approaches for fabricating nanoparticle structures are promising for new advanced materials [3,11] and have attracted significant attention for real applications, such as nanocoatings and sensors. [8,10,12] Meanwhile, the demand for green manufacturing techniques has dramatically increased due to environmental pressures. [13] Some of the many green strategies include: utilizing alternative feedstock through biorefinery development; [14] identifying more economical reactions; using green solvents, such as ionic liquids, supercritical carbon dioxide (scCO 2 ), and other environmentally benign organic solvents; [15] and optimizing synthetic methodologies for creating advanced materials out of nanoparticle building blocks. [16] Since green chemistry has been successful on many fronts in pharmaceuticals, [17] scientists and engineers are optimistic about integrating clean manufacturing techniques into nanoscience to develop high-precision, low-waste fabrication methods. [18] In addition, green manufacturing techniques improve public perception of nanoscience by creating a responsible attitude toward the development of new technology.Inspired by natural dewetting phenomena, such as the coffee-ring effect and wine tears, researchers have designed strategies for the controlled assembly of colloidal particles into larger, ordered structures. Dimitrov and Nagayama developed a method of colloidal deposition for polycrystalline monolayer films at the air-liquid-solid interface, [19] and Jiang et al. used a similar approach to fabricate photonic structures. [20] Through this method, gold nanoparticle films were produced, [21] which may serve as an excellent matrix for laser desorption ionization mass spectrometry. [22] Despite hazardous materials involved in nanoparticle synthesis, colloidal deposition is regarded as a greener technique as it reduces or eliminates the use or Inspired by natural dewetting phenomena, such as the coffee-ring effect, researchers are developing strategies for the controlled assembly of colloidal particles into functional nanoparticle conglomerates. Colloidal assembly techniques are regarded as green methods as they reduce or eliminate the use or generatio...