Benzene (C 6 H 6 ), while stable under ambient conditions, can become chemically reactive at high pressures and temperatures, such as under shock loading conditions. Here, we report in situ x-ray diffraction and small angle x-ray scattering measurements of liquid benzene shocked to 55 GPa, capturing the morphology and crystalline structure of the shock-driven reaction products at nanosecond timescales. The shock-driven chemical reactions in benzene observed using coherent XFEL x-rays were a complex mixture of products composed of carbon and hydrocarbon allotropes. In contrast to the conventional description of diamond, methane and hydrogen formation, our present results indicate that benzene’s shock-driven reaction products consist of layered sheet-like hydrocarbon structures and nanosized carbon clusters with mixed sp 2 - sp 3 hybridized bonding. Implications of these findings range from guiding shock synthesis of novel compounds to the fundamentals of carbon transport in planetary physics.

Nanoconfinement of ionic liquids (ILs) influences their physicochemical properties. In this study, we investigate the effect of soft nanoconfinement imposed by lyotropic liquid crystals (LLCs) on ILs. The LLC ion gels are obtained through self-assembly of a short chain block copolymer (BCP) of polyethylene-block-poly(ethylene oxide), PE-b-PEO, in ILs. The effect of confinement on the interaction of ions with PEO is investigated through electrochemical impedance spectroscopy (EIS) and carbon dioxide (CO2) absorption measurements. The results show that the synergistic effect on the CO2 absorption capacity of LLC ion gels takes place as a result of confinement. Formation of IL pathways through the LLC increases the CO2 solubility, absorption capacity, and absorption rate. Increasing the concentration of block copolymer in the LLC structure enhances the dissociation of ILs and consequently lowers CO2 absorption. Therefore, the competing effects of confinement and IL-PEO interaction control the properties of LLC ion gels.

Hierarchically structured emissive quantum dot (CdS/CdSe) poly(ionic liquid) composites are synthesized through colloidal polymerization within a lyotropic liquid crystal, yielding a solvent-responsive nanoparticle (NP) composite possessing four ordered structural motifs. The composite is prepared by coassembling an amphiphilic ionic liquid (IL) monomer, 3-decyl-1-vinylimidazolium chloride, [C(10)VIm(+)][Cl-], and IL monomer, 3-(10-mercaptodecyl)-1-vinylimidazolium bromide surface-functionalized quantum dots, QD-[SC(10)VIm(+)][Br-], in 30 wt % water. Photo (UV)-initiated free radical polymerization serves to form a colloidal copolymer that collimates pairs of QDs within the core of large cylinders (average diameter = 21 nm and length = 422 nm), as evidenced by ultrasmall-angle X-ray scattering (USAXS). As revealed by continuous wave terahertz multispectral reconstructive 3-D imaging, the subsurface structure along the cylinder axis undergoes dynamic rearrangement between 2D hexagonal and cubic packing. The polymerized ionic liquid sheath surrounding the QDs is composed of concentric hexagonally perforated lamellae (HPL) with an interlamellar repeat distance of 3 nm, as determined by small-angle X-ray scattering (SAXS). The encapsulated QDs retain crystallinity (TEM and WAXS) and emission characteristics (photoluminescence spectroscopy, lambda(EM) = 638 nm). Phenomenological time-dependent Ginzburg-Landau calculations verify the mesoscale cylinders arise from the topological constraints imposed by the in-plane perforations of the polymerized ionic liquid as it wraps around the hard (unmalleable) spherical QDs.

X-ray scattering and transmission electron microscopy carried out on unpurified soot recovered from open air detonations of a liquid explosive mixture of nitromethane (95 (v/v) % and diethylenetriamine 5 (v/v) % sensitizer determined primary particles possessing a hollow spherical core (d(avg). = 6.9 nm) coated in a sp(2)-hybridized carbon shell of similar to 4.2 nm thick. Similar nanophase carbons have been previously reported in studies on closed chamber detentions of composition B in air. Given the noted changes in charge size, explosive composition, and peak temperature and pressure between the two detonations, we hypothesize the formation of the nanocarbons are attributed to excess H2O (detonation byproduct and/or atmospherically-derived) and atmospherically-derived O-2. The H2O is hypothesized to be the determining component leading to the formation of non-planar (curved), sp(2)-hybridized carbon frameworks, necessary for assembly into spherical particles. Excess O-2 produces after-burn, an oxidizing environment sufficient to possibly create the interior voids.

Single unit process fabrication of a responsive Ag nanoparticle (NP) chemical hydrogel composite is achieved through digital visible light processing (DLP) 3D printing of a self-assembled nanostructured (multilamellar) resin doped with Ag(i).

Amphiphilic block copolymers self-assemble at the water/oil interface to form different mesomorphic structures, such as lamellar, micellar cubic, normal hexagonal, and reverse hexagonal structures. Usually, these structures are polycrystalline and the value of their elastic modulus depends on the average orientation of their constituent's single crystals. We provide a model to predict the elastic modulus and yielding of mesophases from their characteristic length and intermicellar interactions. Shear modulus of each structure is calculated as a function of deformation (strain). Zero-shear modulus, G(0), depends on the inverse of the intermicellar distance with a power law model. The power law index for each structure is approximately n + 2 where n is the degree of confinement in the mesophase: 1 for lamellar, 2 for both normal and reverse hexagonal, and 3 for micellar cubic structures. Rheological properties of different mesophases of Pluronic P84 in the presence of water and p-xylene are used as a case study. The model is found to be in good agreement with experimental data in the linear viscoelastic region. When compared to experimental data, the yield strain value obtained from the model is one order of magnitude higher than the limit of the linear viscoelastic regime and close to the strain at the cross-over point of storage and loss moduli. Frequency sweep measurements are done to characterize the relaxation and cooperative model behaviors of each mesophase structure.

Combining bottom-up self-assembly with top-down 3D photoprinting affords a low cost approach for the introduction of nanoscale features into a build with low resolution features.

Dynamic plasmonic tuning of Au NP organization through pH and temperature mediated polymer architecture transformation from lamellar to bicontinuous cubic.

Transit through the carbon liquid phase has significant consequences for the subsequent formation of solid nanocarbon detonation products. We report dynamic measurements of liquid carbon condensation and solidification into nano-onions over ∽200 ns by analysis of time-resolved, small-angle X-ray scattering data acquired during detonation of a hydrogen-free explosive, DNTF (3,4-bis(3-nitrofurazan-4-yl)furoxan). Further, thermochemical modeling predicts a direct liquid to solid graphite phase transition for DNTF products ~200 ns post-detonation. Solid detonation products were collected and characterized by high-resolution electron microscopy to confirm the abundance of carbon nano-onions with an average diameter of ∽10 nm, matching the dynamic measurements. We analyze other carbon-rich explosives by similar methods to systematically explore different regions of the carbon phase diagram traversed during detonation. Our results suggest a potential pathway to the efficient production of carbon nano-onions, while offering insight into the phase transformation kinetics of liquid carbon under extreme pressures and temperatures.

This work describes the kinetics of thermal polymerization in nanoconfined domains of lyotropic liquid crystal (LLC) templates by using chemorheological studies at different temperatures. We investigate lamellar and reverse hexagonal LLC phases with the same concentration of the monomeric phase. Results show that the mesophase structures remain intact during thermal polymerization with very slight changes in the domain size. The polymerization rate decreases in the nanoconfined structure compared to the bulk state due to the segregation effect, which increases the local monomer concentration and enhances the termination rate. Additionally, the polymerization rate is faster in the studied reverse hexagonal systems compared to the lamellar ones due to their lower degree of confinement. A higher degree of confinement also induces a lower monomer conversion. Differential scanning calorimetry confirms the obtained results from chemorheology.

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We show that olefin metathesis can be used in an extremely simple process to rapidly alter the morphology of self-assembled poly(butadiene-b-ethylene oxide) (PB–PEO) dispersions in situ. The addition of a water-insoluble Hoveyda–Grubbs catalyst to aqueous assemblies of PB–PEO leads to degradation of the hydrophobic PB block by well-established metathesis pathways and a concomitant change in the composition of the block copolymer. This phenomenon drives morphological transitions characterized by rapidly decreasing sizes of the self-assembled aggregates, the ultimate extent of which is readily controlled by catalyst concentration. Exemplary cases are presented in which transitions from worm-like micelles to spherical micelles or from vesicles to worm-like micelles can be accomplished within minutes.

The study of solid carbon (nanocarbon) nucleation and growth from detonating high explosives is limited because of the difficulty directly evaluating chemical reactions behind the shock front. Understanding the correlation between detonation conditions and nanocarbon formation requires isolation, purification, and analysis of the carbon products. Aqueous density fractionation of products recovered from a colliding wave TATB-based high explosive (PBX9502) detonation are evaluated as an environmentally benign, "green" chemical processing approach for the separation of carbon materials from metal and metal oxide byproducts. Recovery of material sufficient for X-ray scattering analysis was obtained in two fractions. X-ray scattering showed the less dense fraction (rho < 1 g/cm(3)) contains hollow spherical core (d(avg) = 27.8 nm) nanoparticles with a shell (thickness = 3.6 mn) composed of predominately sp(2) hybridized carbon. Particles contained within the dense fraction (rho > 1 g/cm(3)) were a mixture of oblate spheroids (major axis length = 43.8 am and minor axis = 2.9 mn) and small polydisperse solid spherical particles (d(avg) = 2.4 mn) composed of both sp(2) and sp(3) bonded carbon with residual contamination ti-oin the brass detonators.