Placement control of nanomaterial arrays on the surface-reconstructed block copolymer thin films.
ABSTRACT We present a control strategy for the facile placement of densely packed nanomaterial arrays (i.e., nanoparticles and nanorods) on surface reconstructed polystyrene-block-poly(methyl methacrylate) thin film patterns. The surface reconstruction of perpendicularly oriented block copolymer thin films, which were produced by a treatment with selective solvent vapors for both blocks, created the topographical nanopatterns with enough height contrast for nanoparticle deposition without the need for additional selective etching of a single block domain. The deposition method of nanomaterials was also optimized, and densely packed one- and two-dimensional nanomaterials arrays in the grooves of the block copolymer film patterns were fabricated efficiently. Then, we demonstrated that height contrast of the surface reconstructed block copolymer films could be reversed by electron beam irradiation resulting in nanomaterial arrays placed at the mesa phase of the nanopatterns. On the basis of this nanomaterial placement control strategy, dual nanomaterial arrays on a single block copolymer pattern were also realized.
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ABSTRACT: The dispersion, local orientation and optical absorption of polystyrene (PS, degree of polymerization P) nanocomposites containing PS-grafted gold nanorods (Au NRs, PS degree of polymerization N), with aspect ratios ([small nu] = length/diameter) ranging from 2.5 to 6.3, are studied using quantitative scanning electron microscopy (SEM) and optical spectroscopy. The experimentally observed nanorod assemblies and optical absorptions are compared with predictions from self-consistent field theory (SCFT) and finite difference time domain (FDTD) calculations, respectively. A pair correlation function for Au NRs is calculated from SEM images, and contains no correlation peaks for P/N = 0.9, indicating nanorods are dispersed within the nanocomposite. Large correlation peaks are observed for P/N = 7.6, representative of interparticle separation distances within nanorod aggregates, which do not vary with [small nu]. On the basis of SCFT calculations, aggregation is attributed to significant depletion-attractionSoft Matter 01/2014; · 4.15 Impact Factor
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ABSTRACT: Surface nano-patterns on substrates are the fundamental structures of various nano-devices. Template-based surface nano-patterning techniques are highly efficient methods in realizing different surface nano-patterns. The time-saving and low-cost fabrication processes of the template-based surface patterning are highly desirable for industry in fabricating different kinds of nano-devices. This tutorial review summarizes the recent advancements in the field of template-based surface nano-patterning, especially focusing on three templates prepared using self-assembly processes: ultra-thin alumina membranes, monolayer polystyrene sphere arrays, and block copolymer patterns. The basic concepts, the general fabrication processes, the structure-related properties, and the device applications of these template-based surface nano-patterning techniques are introduced.Chemical Society Reviews 10/2010; 40(3):1247-58. · 24.89 Impact Factor
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ABSTRACT: Fabrication of modern nanomaterials and nanostructures with specific functional properties is both scientifically promising and commercially profitable. The preparation and use of nanomaterials require adequate methods for the control and characterization of their size, shape, chemical composition, crystalline structure, energy levels, pathways and dynamics of physical and chemical processes during their fabrication and further use. In this review, we discuss different instrumental methods for the analysis and metrology of materials and evaluate their advantages and limitations at the nanolevel.Nanoscale 08/2013; · 6.73 Impact Factor