Optical Nanoengineering Optics and electronics operate at very different length scales. Surface plasmons are light-induced electronic excitations that being pursued as a route to bridge the scales bring processing speed offered by optical communication down size of chip circuitry. Now, Fan et al. (p. 1135 ) describe self-assembly nanoscale dielectric particles coated with gold. Functionalization gold surface polymer ligands allowed controlled production clusters nanoparticles. The properties...

When small numbers of colloidal microspheres are attached to the surfaces liquid emulsion droplets, removing fluid from droplets leads packings spheres that minimize second moment mass distribution. The structures range sphere doublets, triangles, and tetrahedra exotic polyhedra not found in infinite lattice packings, molecules, or minimum-potential energy clusters. system presents a route produce new means study how different physical constraints affect symmetry parcels matter.

Assemblies of strongly interacting metallic nanoparticles are the basis for plasmonic nanostructure engineering. We demonstrate that clusters four identical spherical particles self-assembled into a close-packed asymmetric quadrumer support strong Fano-like interference. This feature is highly sensitive to polarization incident electric field due orientation-dependent coupling between in cluster. structure demonstrates how careful design colloidal systems can lead creation new modes and...

The study of clusters has provided a tangible link between local geometry and bulk condensed matter, but experiments have not yet systematically explored the thermodynamics smallest clusters. Here we present experimental measurements structures free energies colloidal in which particles act as hard spheres with short-range attractions. We found that highly symmetric are strongly suppressed by rotational entropy, whereas most stable anharmonic vibrational modes or extra bonds. Many these...

Curving Crystals When a material with different set of lattice parameters is grown on the surface crystal second material, stresses at interface can affect growing crystal. Meng et al. (p. 634 ) studied growth colloidal crystals top curved water droplet. Owing to elastic stress caused by bending crystal, strong distortions occurred in but, nonetheless, large single-crystalline domains no topological defects were formed.

Abstract Structurally colored materials could potentially replace dyes and pigments in many applications, but it is challenging to fabricate structural colors that mimic the appearance of absorbing pigments. We demonstrate microfluidic fabrication “photonic pigments” consisting microcapsules containing dense amorphous packings core–shell colloidal particles. These show non‐iridescent are independent viewing angle, a critical requirement for applications such as displays or coatings. design...

DNA control of bonding interactions Colloidal particles have been used as atom mimics and are often connected together using complementary strands. Rogers Manoharan controlled the strength colloidal “bond” by a set competing strand displacement reactions. They capitalized on reversible chemical equilibrium between strands connecting different to temperature dependence state. Science , this issue p. 639

Low shrinkage, no high-temperature treatment, and greater versatilityare some of the advantages method for fabricating ordered macroporous materials presented here—assembly ultrafine colloidal particles oxides (rather than alkoxide precursors) using monodisperse polystyrene as a template. The Figure shows silica made from Snowtex ZL suspension.

Mix a drop of water into vial oil. With some surfactant and vigorous shake, that one droplet has become thousands, the total interfacial area increased by an order magnitude or more. Like folded membranes in our mitochondria, alveoli lungs, catalytic converters cars, oil-water emulsions contain vast reservoir can be used to control transform things encounter it. The interface is especially well-suited directing assembly colloidal particles, which bind it rapidly often irreversibly.

Most of the colloidal clusters have been produced from oil-in-water emulsions with identical microspheres dispersed in oil droplets. Here, we present new types binary phase-inverted water-in-oil using various combinations two different colloids several size ratios: monodisperse silica or polystyrene for larger particles and titania nanoparticles smaller particles. Obviously, a better understanding how finite groups self-organize confined geometry may help us control structure matter at...

Colloidal glasses, bird feathers, and beetle scales can all show structural colors arising from short-ranged spatial correlations between scattering centers. Unlike the Bragg diffraction in ordered materials like opals, of these photonic glasses are independent orientation, owing to their disordered, isotropic microstructures. However, there few examples with angle-independent red nature, colloidal particle sizes chosen yield weak color saturation. Using theory, we that absence be explained...

DNA nanotechnology provides a versatile foundation for the chemical assembly of nanostructures. Plasmonic nanoparticle assemblies are particular interest because they can be tailored to exhibit broad range electromagnetic phenomena. In this Letter, we report DNA-functionalized nanoparticles into heteropentamer clusters, which consist smaller gold sphere surrounded by ring four larger spheres. Magnetic and Fano-like resonances observed in individual clusters. The plays dual role: it...

Ultrasmooth, highly spherical monocrystalline gold particles were prepared by a cyclic process of slow growth followed chemical etching, which selectively removes edges and vertices. The etching effectively makes the surface tension isotropic, so that spheres are favored under quasi-static conditions. It is scalable up to particle sizes 200 nm or more. resulting crystals display uniform scattering spectra consistent optical coupling at small separations, even showing Fano-like resonances in...

High-speed tracking of single particles is a gateway to understanding physical, chemical, and biological processes at the nanoscale. It also major experimental challenge, particularly for small, nanometer-scale particles. Although methods such as confocal or fluorescence microscopy offer both high spatial resolution signal-to-background ratios, emission lifetime limits measurement speed, while photobleaching thermal diffusion limit duration measurements. Here we present method based on...

Plasmonic nanoparticle assemblies are a materials platform in which optical modes, resonant frequencies, and near-field intensities can be specified by the number position of nanoparticles cluster. A current challenge is to achieve clusters with higher yields new types shapes. In this Letter, we show that broad range plasmonic nanoshell nanoclusters assembled onto lithographically defined elastomeric substrate relatively high using templated assembly. We assemble measure properties three...

The formation of a viral capsid -- the highly-ordered protein shell that surrounds genome virus is canonical example self-assembly. capsids many positive-sense RNA viruses spontaneously assemble from in vitro mixtures coat and RNA. high yield proper remarkable, given their structural complexity: 180 identical proteins must arrange into three distinct local configurations to form an icosahedral with triangulation number 3 (T = 3). Despite wealth data studies simulations, even most fundamental...

Disordered nanostructures with correlations on the scale of visible wavelengths can show angle-independent structural colors. These materials could replace dyes in some applications because color is tunable and resists photobleaching. However, designing a prescribed difficult, especially when application -- cosmetics or displays, for example requires specific component materials. A general approach to solving this constrained design problem modeling optimization: using model that predicts...

An emulsion encapsulation and shrinkage technique for producing large quantities of colloidally stable clusters microspheres (see Figure) is demonstrated. In spite differences in particle properties interactions, the sequence cluster packings remains same three different systems, suggesting that sphere-packing process can be successfully applied to a wide range colloidal materials.

A microfluidic device is used to generate uniform emulsion droplets containing monodisperse latex spheres at specific intervals by shearing off the tip of incoming aqueous phase junction two channels (see Figure). The water‐in‐oil emulsions are converted colloidal assemblies slowly removing water from droplets.

We calculate the ground states of hard-sphere clusters, in which $n$ identical hard spherical particles bind by isotropic short-ranged attraction. Combining graph theoretic enumeration with basic geometry, we analytically solve for clusters $n\ensuremath{\le}10$ satisfying minimal rigidity constraints. For $n\ensuremath{\le}9$ state degeneracy increases exponentially $n$, but $n>9$ decreases due to formation structures $>3n\ensuremath{-}6$ contacts. Interestingly, $n=10$ and possibly at...