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A template with macroscopically aligned nanopatterns can be an effective vehicle for arranging nanoscale particles or rods in a particular orientation to achieve their anisotropic properties. A room-temperature process is also desirable for nanoscale patterning of heat-sensitive functional molecules such as organic fluorophores. Here, large-area orientation of nanodomains of block copolymers is demonstrated by simultaneous shearing and solvent vapor annealing at room temperature. The shear-aligned nanodomains are applied to a chemical template for nanoscale patterning of green fluorescent molecules. In addition, the grooved nanochannels obtained from the macroscopically aligned nanodomains work as a physical template for guiding Au nanorods to end-to-end assemblies which exhibit the polarization-dependent plasmonic extinction. [ABSTRACT FROM AUTHOR]

The ability to organize metal nanoparticles over the macroscopic length scale has fundamental implications for advanced plasmonic applications. In particular, linear assemblies of anisotropic nanorods (NRs) may represent a dichroic superstructure, in which plasmonic extinction is inherently dependent on the direction of light polarization. As plasmonic properties are interconnected with optics, electronics, catalysis, and sensing, dichroism in plasmonic systems can stimulate interesting opportunities in many fields of chemistry. However, the preparation of dichroic structures with a single orientation at the centimeter scale remains a significant challenge. Herein, directed self‐assemblies of polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) diblock copolymers on lithographical patterns are applied to produce a linear pattern of Au NRs. Periodic nanogrooves from plasma‐etched PS‐b‐PMMA nanodomains facilitate the dense packing of Au NRs into end‐to‐end alignment, which entail strong plasmonic coupling among longitudinal plasmonic modes. Because the resulting NR assemblies have uniform orientation, their dichroic functions can be examined by conventional UV–vis spectroscopy without the aid of single‐particle measurements. Interestingly, both transverse and longitudinal localized surface plasmonic resonance peaks can be turned on and off under two polarized lights in orthogonal directions. Moreover, the resulting superstructures can be transferred onto various substrates, allowing the implantation of dichroic functions for numerous plasmonic applications. [ABSTRACT FROM AUTHOR]