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Sharon Glotzer enjoys a riveting tale of derring-do in materials science.

Non-equilibrium two-dimensional melting is less understood than its equilibrium counterpart. Now it is shown that topologically driven melting in a two-dimensional crystal of charged colloids is the same irrespective of the mechanisms that generate the defects

To mark the inaugural issue of Nature Chemical Engineering, we asked a collection of scientists working in different branches of chemical engineering to share their perspectives on the challenges and opportunities that lie ahead for their respective fields.

Photonic crystals have a range of desirable properties for manipulating light. Here, the authors calculate and use the photonic band gap for thousands of such crystals to examine heuristics for their design and predict new photonic crystal structures.

All hard, convex shapes pack more densely than spheres, although for tetrahedra this was demonstrated only very recently. Here, tetrahedra are shown to pack even more densely than previously thought. Thermodynamic computer simulations allow the system to evolve naturally towards high-density states, showing that a fluid of hard tetrahedra undergoes a first-order phase transition to a dodecagonal quasicrystal, and yielding the highest packing fractions yet observed for tetrahedra.

The interfacial energy between a macroscopic surface consisting of different materials and a liquid is independent of the surface structure. It is now shown that because of the way in which a multicomponent nanoscale surface affects the solvent–molecule arrangement, it is both the surface structure and composition that dictate the interfacial energy.

An atomic stencilling method based on the co-adsorption of iodide and 2-naphthalenethiol on gold is described, yielding more than 20 different types of nanoparticle with masked and painted regions and patchy particle morphologies not reported previously.

Inorganic nanoparticles with non-uniform size distributions can spontaneously assemble into uniformly sized supraparticles with core-shell morphologies.

In 1984, scientists made a crystalline alloy that had a seemingly impossible arrangement of atoms. They had discovered the first quasicrystal — a type of material that transformed ideas about how atoms can be ordered in solids.

A superlattice structure of gold tetrahedra formed via a surface-promoted pathway is reported. The octo-diamond crystal is achiral, but exhibits bilayers of left- and right-handed chiral motifs with chiroptical plasmonic responses.

Spherical micelles can aggregate into highly organized structures. New micelle arrangements mimic known atomic crystals, both periodic and aperiodic, and provide evidence for a material with 18-fold rotational symmetry.

Networks of notches in nanocomposite sheets prevent unpredictable local failure and increase the ultimate strain of the sheets from 4% to 370% without affecting their electrical conductance.

Achieving simultaneous high storage and loss moduli in gels is difficult due to the opposite chemical structure requirements needed for such properties. Here the authors show a spectrum of gels containing CdTe nanoparticles stabilized by glutathione that have such properties which can be rationalised through the developed model.

The complex 3D structure of a quasicrystalline binary nanocrystal superlattice has been resolved by electron microscopy and tomography.

Symmetrical protein oligomers perform key structural and catalytic functions in nature, but engineering such oligomers synthetically is challenging. Now, oppositely supercharged synthetic variants of normally monomeric proteins have been shown to assemble via specific, introduced electrostatic contacts into symmetrical, highly well-defined oligomers.

The pathways available for self-assembly are affected by the shape anisotropy of the building blocks, but the details are still unclear. Here, Hsiao et al. show that colloidal discoids self-assemble into metastable states with orientational order when kinetic trapping is incorporated as a design principle.

Disks interacting via particular potentials self-organize into triangles that stabilize mosaics with 10-, 12-, 18- and 24-fold symmetry, as revealed by computer simulations. Discoveries of further novel quasicrystals may now be within reach.

Clathrates—open crystals with a hierarchy of polyhedral cages—are mostly found in atomic and molecular systems. Now, it has been shown through Monte Carlo simulations that the formation of colloidal host–guest clathrates can be driven by entropy alone, through entropy compartmentalization.

The DNA-mediated assembly of anisotropic gold nanoparticles shows the importance of particle shape in the controlled formation of DNA–nanoparticle superlattices.

Symmetry breaking in colloidal crystals is achieved with DNA-grafted programmable atom equivalents and complementary electron equivalents, whose interactions are tuned to create anisotropic crystalline precursors with well-defined coordination geometries that assemble into distinct low-symmetry crystals.

Guiding the assembly pathway of a nanoparticle system toward multiple superstructures while visualizing in situ remains challenging. Here the authors combine liquid-cell transmission electron microscopy, scaling theory and molecular dynamics simulations to image and quantify self-assembly processes of gold nanocubes into distinct superlattices.

Patchy nanoparticles are desirable building blocks for the guided assembly of functional superstructures. Here, the authors demonstrate quantitative control over asymmetric polymer grafting on triangular Au nanoprisms based on polymer scaling theory.

Fivefold and icosahedral symmetries in multiply twinned crystals can be used to influence the shape of synthetic nanoparticles. Simulations now show the entropy-driven formation of fivefold and icosahedral twinned clusters of truncated tetrahedra that self-assemble into colloidal crystals.

Fluids may avoid crystallization via an underlying mechanism that remains hotly debated. Teich et al. show that hard polyhedral particles form glass because of the competition of local structural motifs, each of which is prevalent in crystals self-assembled from particles of closely related shapes.

The rational design and assembly of colloidal quasicrystals is achieved by exploring the hybridization of nanoscale decahedra nanoparticles functionalized with DNA linkers.

Quasicrystals exhibit long-range order without periodicity. The authors report an approach for quasicrystal fabrication and show through in situ imaging and corresponding simulations the formation of a single decagonal quasicrystal arising from coalescence of multiple quasicrystals in a liquid.

Unravelling the formation of binary nanocrystal phases is challenging. Here, by combining in situ small-angle X-ray scattering and molecular dynamics simulations, we show that AlB₂ and NaZn₁₃ superlattices undergo classical homogeneous nucleation consistent with the presence of short-range attractive interactions guiding the crystallization process.

Ordered self-assembly is a promising way to realize collective properties in nanocrystals, but reliable routes to such macroscopic structures are missing. Here the authors make cm-scale ordered superlattice films from gold nanoclusters, correlating film properties with the shape of the building blocks

What do you get when you cross a crystal with a quasicrystal? The answer is a structure that links the ancient tiles of Archimedes, the iconic Fibonacci sequence of numbers and a book from the seventeenth century.

The ligand-mediated binding of colloid particles to each other is more effective if the particles are flat rather than curved. This finding opens up opportunities for the design of self-assembling materials.

Self-organization of nanoparticles allows the assembly of complex structures with distinct properties. Here, the authors combine similarly charged nanoparticles with proteins to form hybrid organic/inorganic supraparticles, capable of incorporating biological components.

Preparing crystals held together with macromolecular bonds can create shape memory materials that can be engineered to exhibit a wide range of reversible changes useful for chemical sensing, optics and robotics.

Experiments and computer simulations show that Janus ellipsoids can self-assemble into self-limiting fibres that have shape-memory properties and can be actuated by applying an external electric field.

Self-limited assembly of 'imperfect' chiral nanoparticles enables formation of bowtie-shaped microparticles with size monodispersity and continuously variable chirality to be used for printing photonically active metasurfaces.

Janus colloids with an attractive patch on the surface are model systems to explore structure formation but experimental realizations of such particles are rare. Here, the authors report a scalable method to precisely vary the Janus balance over a wide range and observe the formation of various structures including fibers, bilayers, and nonequilibrium rings catalyzed by substrate binding.

Solid-state sensors for the detection of heavy-metal cations require for the most part sophisticated chemistry and equipment. It is now shown that toxic cations in environmental samples can be detected with ultrahigh sensitivity and over a broad range of cation concentrations by measuring the tunnelling current across films of nanoparticles decorated with striped monolayers of organic ligands.

Thin lanthanide fluoride nanoplates are shown to self-organize at the liquid/air interface into long-range-ordered two-dimensional planar tilings. In this joint experimental–computational, multiscale investigation, the assembly behaviour is shown to be dictated by entropic forces arising from particle shape and enthalpic forces arising from interaction anisotropy.

A body-centred icosahedral quasicrystal has been assembled, by using molecular dynamics simulations, from a one-component fluid of particles interacting via a tunable, isotropic pair potential.

Two separate studies show how DNA tiles can be used in automated assembly processes: one system self-replicates, the second assembles the output of a molecular computation.

The nanometre scale is a brave new world for scientists — mixing materials at such small dimensions can cause all sorts of surprising effects. New studies of experimental systems on the nanoscale further our understanding of these complex phenomena.