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The reduction in the inner diameter of the nanotoroids of a π-conjugated barbiturate monomer results in nano-[2]catenanes in a high yield due to enhanced secondary nucleation and subsequent steric suppression of further catenation.

Helical folding of randomly coiled linear polymers is an essential organization process not only for biological polypeptides but also for synthetic functional polymers. Realization of this dynamic process in supramolecular polymers (SPs) is, however, a formidable challenge because of their inherent lability of main chains upon changing an external environment that can drive the folding process (e.g., solvent, concentration, and temperature). We herein report a photoinduced reversible folding/unfolding of rosette-based SPs driven by photoisomerization of a diarylethene (DAE). Temperature-controlled supramolecular polymerization of a barbiturate-functionalized DAE (open isomer) in nonpolar solvent results in the formation of intrinsically curved, but randomly coiled, SPs due to the presence of defects. Irradiation of the randomly coiled SPs with UV light causes efficient ring-closure reaction of the DAE moieties, which induces helical folding of the randomly coiled structures into helicoidal ones, as evidenced by atomic force microscopy and small-angle X-ray scattering. The helical folding is driven by internal structure ordering of the SP fiber that repairs the defects and interloop interaction occurring only for the resulting helicoidal structure. In contrast, direct supramolecular polymerization of the ring-closed DAE monomers by temperature control affords linearly extended ribbon-like SPs lacking intrinsic curvature that are thermodynamically less stable compared to the helicoidal SPs. The finding represents an important concept applicable to other SP systems; that is, postpolymerization (photo)reaction of preorganized kinetic structures can lead to more thermodynamically stable structures that are inaccessible directly through temperature-controlled protocols.

Iron nitride (Fe3N) and iron carbide (Fe3C) nanoparticles can be prepared via sol–gel synthesis. While sol–gel methods are simple, it can be difficult to control the crystalline composition, i.e., to achieve a Rietveld-pure product. In a previous in situ synchrotron study of the sol–gel synthesis of Fe3N/Fe3C, we showed that the reaction proceeds as follows: Fe3O4 → FeOx → Fe3N → Fe3C. There was considerable overlap between the different phases, but we were unable to ascertain whether this was due to the experimental setup (side-on heating of a quartz capillary which could lead to thermal gradients) or whether individual particle reactions proceed at different rates. In this paper, we use in situ wide- and small-angle X-ray scattering (wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS)) to demonstrate that the overlapping phases are indeed due to variable reaction rates. While the initial oxide nanoparticles have a small range of diameters, the size range expands considerably and very rapidly during the oxide–nitride transition. This has implications for the isolation of Rietveld-pure Fe3N, and in an extensive laboratory study, we were indeed unable to isolate phase-pure Fe3N. However, we made the surprising discovery that Rietveld-pure Fe3C nanoparticles can be produced at 500 °C with a sufficient furnace dwell time. This is considerably lower than the previous reports of the sol–gel synthesis of Fe3C nanoparticles.

Synthesis of one-dimensional nanofibers with distinct topological (higher-order structural) domains in the same main chain is one of the challenging topics in modern supramolecular polymer chemistry. Non-uniform structural transformation of supramolecular polymer chains by external stimuli may enable preparation of such nanofibers. To demonstrate feasibility of this post-polymerization strategy, we prepared a photoresponsive helically folded supramolecular polymers from a barbiturate monomer containing an azobenzene-embedded rigid p -conjugated scaffold. In contrast to previous helically folded supramolecular polymers composed of a more flexible azobenzene monomer, UV-light induced unfolding of the newly prepared helically folded supramolecular polymers occurred nonuniformly, affording topologically blocky copolymers consisting of folded and unfolded domains. The formation of such blocky copolymers indicates that the photoinduced unfolding of the helically folded structures initiates from relatively flexible parts such as termini or defects. Spontaneous refolding of the unfolded domains was observed after visible-light irradiation followed by aging to restore fully folded structures. .

Mechanical interlocking of molecules (catenation) is a nontrivial challenge in modern synthetic chemistry and materials science

Laboratory education is a defining feature of chemistry degree courses, with one of the fundamental aims being acquiring competency in a range of chemistry-specific practical skills, yet there are still limited reports of direct assessment of these skills. Here, we present the development, implementation, and evaluation of a station-based practical chemistry exam for first year undergraduate students. We have designed the exam to explicitly assess a range of practical chemistry skills that we highlighted as being essential for subsequent chemistry laboratory work in our degree program, including many final year independent research projects. Details are provided on the logistics of implementing this exam, which has run for cohorts of 50–120 and is suitable for cohorts of up to 200 students. Introducing the practical exam into our course has received positive feedback from both staff and students and has contributed to increased motivation to learn and retain practical chemistry skills.

Contrast-variation small-angle neutron scattering (CV-SANS), small-angle X-ray scattering (SAXS), nuclear magnetic resonance (NMR) measurements of diffusion and isothermal titration calorimetry (ITC) are used to gain insight into the aggregation of an alkyl-C60 derivative, molecule 1, in n-hexane, n-decane and toluene as a function of concentration and temperature. Results point to an associative mechanism of aggregation similar to other commonly associating molecules, including non-ionic surfactants or asphaltenes in non-aqueous solvents. Little aggregation is detected in toluene, but small micelle-like structures form in n-alkane solvents, which have a C60-rich core and alkyl-rich shell. The greatest aggregation extent is found in n-hexane, and at 0.1 M the micelles of 1 comprise around 6 molecules at 25 °C. These micelles become smaller when the concentration is lowered, or if the solvent is changed to n-decane. The solution structure is also affected by temperature, with a slightly larger aggregation extent at 10 °C than at 25 °C. At higher concentrations, for example in solutions of 1 above 0.3 M in n-decane, a bicontinuous network becomes apparent. Overall, these findings aid our understanding of the factors driving the assembly of alkyl-π-conjugated hydrophobic amphiphiles such as 1 in solution and thereby represent a step towards the ultimate goal of exploiting this phenomenon to form materials with well-defined order.

Mechanical interlocking of molecules (catenation) is a nontrivial challenge in modern synthetic chemistry and materials science1,2. One strategy to achieve catenation is the design of pre-annular molecules that are capable of both efficient cyclization and of pre-organizing another precursor to engage in subsequent interlocking3–9. This task is particularly difficult when the annular target is composed of a large ensemble of molecules, that is, when it is a supramolecular assembly. However, the construction of such unprecedented assemblies would enable the visualization of nontrivial nanotopologies through microscopy techniques, which would not only satisfy academic curiosity but also pave the way to the development of materials with nanotopology-derived properties. Here we report the synthesis of such a nanotopology using fibrous supramolecular assemblies with intrinsic curvature. Using a solvent-mixing strategy, we kinetically organized a molecule that can elongate into toroids with a radius of about 13 nanometres. Atomic force microscopy on the resulting nanoscale toroids revealed a high percentage of catenation, which is sufficient to yield ‘nanolympiadane’10, a nanoscale catenane composed of five interlocked toroids. Spectroscopic and theoretical studies suggested that this unusually high degree of catenation stems from the secondary nucleation of the precursor molecules around the toroids. By modifying the self-assembly protocol to promote ring closure and secondary nucleation, a maximum catenation number of 22 was confirmed by atomic force microscopy. Nanoscale toroids with a high percentage of poly-catenation and radii of up to about 13 nm are kinetically organized using fibrous supramolecular assemblies with intrinsic curvature and a solvent-mixing strategy.

Kinetically formed metastable molecular assemblies have attracted increasing interest especially in the field of supramolecular polymers. In most cases, metastable assemblies are ensemblies of aggregates based on the same supramolecular motif but with different lengths or sizes, and therefore their kinetic stabilities are experimentally indistinguishable. Herein, we demonstrate a topological effect on kinetic stabilities in a complex mixture of metastable supramolecular polymers. Our azobenzene-incorporated monomer upon heating in nonpolar solvent at ambient temperature kinetically forms complex mixtures of supramolecular polymers with cyclized and open-ended randomly coiled topologies. Upon further heating, we obtained thermodynamically stable twisted fibrils organizing into crystalline fibers. Through the direct visualization of the complex supramolecular polymer mixtures by atomic force microscopy, we demonstrate that the cyclized supramolecular polymer has superior kinetic stability compared to the open-ended species toward the thermal transformation into twisted fibrils. Since the superior kinetic stability of the cyclized species can be attributed to the absence of aggregate termini, we could convert them fully into the thermodynamic species through photoinduced opening of the cyclized structures.

Porous carbons are important for many energy applications. The biopolymer gelatin provides a simple and sustainable route to functional carbon foams with multimodal porosity. In this paper, small angle neutron scattering is applied alongside other techniques to elucidate the mechanism of formation of these foams. Analysis of the data demonstrates that combinations of different metal nitrates can be used to control foam macrostructure. Synergistic interaction of metal ions with the gelatin polypeptide changes the viscoelastic properties and thus controls foam formation.

Supramolecular polymers undergo self-folding on a time scale of days into topologies resembling the protein’s tertiary structures., Folding one-dimensional polymer chains into well-defined topologies represents an important organization process for proteins, but replicating this process for supramolecular polymers remains a challenging task. We report supramolecular polymers that can fold into protein-like topologies. Our approach is based on curvature-forming supramolecular rosettes, which affords kinetic control over the extent of helical folding in the resulting supramolecular fibers by changing the cooling rate for polymerization. When using a slow cooling rate, we obtained misfolded fibers containing a minor amount of helical domains that folded on a time scale of days into unique topologies reminiscent of the protein tertiary structures. Thermodynamic analysis of fibers with varying degrees of folding revealed that the folding is accompanied by a large enthalpic gain. The self-folding proceeds via ordering of misfolded domains in the main chain using helical domains as templates, as fully misfolded fibers prepared by a fast cooling rate do not self-fold.

Surfactant crystallisation is important in many applications in the food, consumer product and medical sectors. However, these processes are not well understood. In particular, surfactant crystallisation can be detrimental to the stability of detergent formulations, such as dish liquid products, resulting in a turbid solution that fails appearance criteria. With the rising global demand for detergent products, understanding the factors that influence formulation stability is of increasing importance. To enable industry to build more robust formulations, it is important to understand the underlying chemistry of the crystallisation process. Here, a model system containing anionic (sodium dodecyl sulfate, SDS) and amphoteric (N,N-dimethyldodecylamine N-oxide, DDAO) surfactants, at concentrations typical of dish liquid products, is studied. Variable temperature

A fluorescent liquid pyrene derivative with a high fluorescence quantum yield (65%) in the bulk state is reported. With this as the sole oil phase, stable luminescent oil-in-water microemulsions have been prepared. Increasing the loading of liquid pyrene swells the droplets, as detected by small-angle neutron scattering. These larger droplets have a greater proportion of pyrene excimer emission contribution in their photoluminescence spectra, which leads to a red shift in the chromaticity of the emission.

Sol–gel chemistry is a powerful tool for the synthesis of porous or nanocrystalline structures of a wide range of materials. The morphology and composition of the final product can be strongly dependent on the mechanism that operates during the heating step, as has been demonstrated in many investigations of binary, ternary, and quaternary metal oxides. We demonstrate the complex phase transformations occurring in a transition-metal carbide (Fe3C, cementite) synthesis using in situ synchrotron X-ray diffraction. Our new study proves the existence of multiple intermediate phases and elucidates how oxide–nitride and nitride–carbide phase transformations can occur. This is particularly important as many transition-metal nitrides and carbides are metastable, which renders their stability windows sensitive to small changes in sol–gel methodology.

Contrast-variation small-angle neutron scattering (CV-SANS), small-angle X-ray scattering (SAXS), nuclear magnetic resonance (NMR) measurements of diffusion and isothermal titration calorimetry (ITC) are used to gain insight into the aggregation of an alkyl-C

Supramolecular assembly can yield ordered structures by taking advantage of the cumulative effect of multiple non-covalent interactions between adjacent molecules. The thermodynamic origin of many self-assembled structures in water is the balance between the hydrophilic and hydrophobic segments of the molecule. Here, we show that this approach can be generalized to use solvophobic and solvophilic segments of fully hydrophobic alkylated fullerene molecules. Addition of n-alkanes results in their assembly—due to the antipathy of ​C60 towards n-alkanes—into micelles and hexagonally packed gel-fibres containing insulated ​C60 nanowires. The addition of pristine ​C60 instead directs the assembly into lamellar mesophases by increasing the proportion of π-conjugated material in the mixture. The assembled structures contain a large fraction of optoelectronically active material and exhibit comparably high photoconductivities. This method is shown to be applicable to several alkyl–π-conjugated molecules, and can be used to construct organized functional materials with π-conjugated sections.

Molecular self-assembly primarily occurs in solution. To better understand this process, techniques capable of probing the solvated state are consequently required. Small-angle scattering (SAS) has a proven ability to detect and characterize solutions, but it is rarely applied to more complex assembly shapes. Here, small-angle X-ray and neutron scattering are applied to observe toroidal assemblies in solution. Combined analysis confirms that the toroids have a core-shell structure, with a π-conjugated core and an alkyl shell into which solvent penetrates. The dimensions determined by SAS agree well with those obtained by (dried-state) atomic force microscopy. Increasing the number of naphthalene units in the molecular building block yields greater rigidity, as evidenced by a larger toroid and a reduction in solvent penetration into the shell. The detailed structural analysis demonstrates the applicability of SAS to monitor complex solution-based self-assembly.

The relationships between molecular architecture, aggregation, and interfacial activity of a new class of CO(2)-philic hybrid surfactants are investigated. The new hybrid surfactant CF2/AOT4 [sodium (4H,4H,5H,5H,5H-pentafluoropentyl-3,5,5-trimethyl-1-hexyl)-2-sulfosuccinate] was synthesized, having one hydrocarbon chain and one separate fluorocarbon chain. This hybrid H-F chain structure strikes a fine balance of properties, on one hand minimizing the fluorine content, while on the other maintaining a sufficient level of CO(2)-philicity. The surfactant has been investigated by a range of techniques including high-pressure phase behavior, UV-visible spectroscopy, small-angle neutron scattering (SANS), and air-water (a/w) surface tension measurements. The results advance the understanding of structure-function relationships for generating CO(2)-philic surfactants and are therefore beneficial for expanding applications of CO(2) to realize its potential using the most economic and efficient surfactants.

Since the first development of surfactant-templated mesoporous silicas, the underlying mechanisms behind the formation of their structures have been under debate. Here, for the first time, time-resolved small-angle neutron scattering (tr-SANS) is applied to study the complete formation of mesoporous silica nanoparticles. A distinct advantage of this technique is the ability to detect contributions from the whole system, enabling the visualization not only of particle genesis and growth but also the concurrent changes to the coexistent micelle population. In addition, using contrast-matching tr-SANS, it is possible to highlight the individual contributions from the silica and surfactant. An analysis of the data agrees well with the previously proposed "current bun" model describing particle growth: Condensing silica oligomers adsorb to micelles, reducing intermicellar repulsion and resulting in aggregation to form initial particle nuclei. From this point, the growth occurs in a cooperative manner, with condensing silica filling the gaps between further aggregating micelles. The mechanistic results are discussed with respect to different reaction conditions by changing either the concentration of the silica precursor or the temperature. In doing so the importance of in situ techniques is highlighted, in particular, tr-SANS, for mechanism elucidation in the broad field of materials science.

An N-methylfulleropyrrolidine (2) bearing three eicosyloxy chains on the laterally substituted phenyl group can be further functionalized to give the ionic fullerene derivative, i.e., N,N-dimethylfulleropyrrolidinium iodide (1). The spectroscopic, electrochemical, self-assembly, and liquid crystalline properties of 1 have been investigated and compared to its neutral precursor 2. Changes in electronic structure upon ionization are observed in the UV spectra. Additionally, a positive potential shift of electrochemical reductions for 1 compared to those of 2 is noted in both homogeneous solution and film state. Driven by the π-π, van der Waals, and electrostatic interactions, the ionic compound 1 is able to form a variety of functional and polymorphic self-assembled structures both from solution and on substrates, including hierarchically organized flakelike microparticles with high water repellency, doughnut-shaped objects with rough surfaces, and long one-dimensional C(60) nanowires (1 μm). The thermotropic behavior of 1 has also been investigated, and a smectic liquid crystalline phase was observed at elevated temperatures. Further investigations of the thermotropic behavior of 1 revealed that a deionization back-reaction from 1 to the neutral precursor 2 gradually occurred. The mechanism of this deionization reaction is presented and discussed. These investigations provide insight into the effects of added ionicity to alkylated fullerene derivatives, in particular on their self-assembly features and functionality.

Catalytic surfactant stabilized gold-containing nanoparticles have been recovered by a new isothermal low-energy approach, by controlled and reversible changes in colloid stability based on fine-tuning of solvent quality. Once recovered, the nanoparticles can be re-dispersed in the solvent, or indeed dispersed into a different solvent. The morphology of the nanoparticles is not significantly affected by the recovery process and they can be used and reused as oxidation catalysts.

Reversed-micelle synthesis has been used to generate CTAB-stabilized gold (Au-NPs) and silver nanoparticles (Ag-NPs). By inducing a phase transition and subsequent separation of the background supporting microemulsion, it has been possible to extract and purify the NPs from the reaction medium. After addition of excess water, the NPs concentrate into an upper octane-rich phase, with impurities and reaction debris (in particular CTAB) partitioning into the water-rich lower phase. UV and (1)H NMR showed that 82% of the original mass of Au-NPs can be purified from the excess CTAB and other salt impurities. The concentrated and purified NPs can be dried down, by solvent removal, and then redispersed in octane. Using the complementary techniques small-angle neutron and X-ray scattering (SANS and SAXS), the structures of microemulsions both with and without nanoparticles prior to separation, and in both upper and lower phases after separation, have been elucidated. The approach has also been applied to the synthesis and recovery of silver nanoparticles, but on a larger scale. This new approach compares favorably with existing methods as it uses no additional organic solvents, has a low-energy demand, and requires no specialist surfactants. The new advance here is that by using a colloidal system to prepare and support the nanoparticles as a structured solvent, a simple soft purification method becomes accessible, which is otherwise impossible with a normal molecular solvent.

A new approach to thicken dense liquid CO(2) is described using the principles of self-assembly of custom-made CO(2) compatible fluorinated dichain surfactants. Solutions of surfactants in CO(2) have been investigated by high-pressure phase behavior, small-angle neutron scattering (HP-SANS) and falling cylinder viscosity experiments. The results show that it is possible to control surfactant aggregation to generate long, thin reversed micellar rods in dense CO(2), which at 10 wt % can lead to viscosity enhancements of up to 90% compared to pure CO(2). This represents the first example of CO(2) viscosity modifiers based on anisotropic reversed micelles.

Graphene is the newest member of the carbon family, and has revolutionized materials science especially in the field of polymer nanocomposites. However, agglomeration and uniform dispersion remains an Achilles' heel (even an elephant in the room), hampering the optimization of this material for practical applications. Chemical functionalization of graphene can overcome these hurdles but is often rather disruptive to the extended pi-conjugation, altering the desired physical and electronic properties. Employing surfactants as stabilizing agents in latex technology circumvents the need for chemical modification allowing for the formation of nanocomposites with retained graphene properties. This article reviews the recent progress in the use of surfactants and polymers to prepare graphene/polymer nanocomposites via latex technology. Of special interest here are surfactant structure-performance relationships, as well as background on the roles surfactant-graphene interactions for promoting stabilization.

This paper describes a powerful and versatile approach that combines the benefits of sol-gel processing with controlled phase separation to yield oxide-carbide-carbon or oxide-nitride-carbon nanocomposites.

Nanoparticles Are Forever: An isothermal low-energy approach permits recovery of nanoparticles for reuse by tuning solvent quality. The recovered and redispersed nanoparticles retain their morphology and chemical reactivity for recycle and reuse. The method, shown here to be effective in the application of nanoparticles as catalysts, will have a wide and general applicability.

Scheme 1. Chemical structures di-chain and tri-chain surfactants.[*] M. J. Hollamby, K. Trickett, A. Mohamed, S. Cummings, R. F. Tabor,O. Myakonkaya, Dr. S. Gold, Prof. J. EastoeSchool of Chemistry, University of BristolCantock’s Close, Bristol, BS8 3DN (UK)Fax: ( +44)117-925-0612E-mail: julian.eastoe@bristol.ac.ukDr. S. Rogers, Dr. R. K. HeenanISIS, STFC-RAL, Didcot, OX11 0QX (UK)[**] K.T.,M.J.H.,S.C.,R.F.T.,S.G.,A.M.,andO.M.thankEPSRC,Kodak,Infineum, HEFCE, the Malaysian government and the School ofChemistry at the University of Bristol for the provision of PhDscholarships. The ISIS-STFC Neutron Scattering Facility (formerlyCCLRC) is thanked for the provision of beamtime and grantstowards consumables and travel. The EPSRC is thanked forprovision of funding under grants EP/C523105/1 and EP/F020686.Supporting information for this article is available on the WWWunder http://dx.doi.org/10.1002/anie.200901543.

Recent improvements in beam-line accessibility and technology have led to small-angle neutron scattering (SANS) becoming more frequently applied to materials problems. SANS has been used to study the assembly, dispersion, alignment and mixing of nanoscale condensed matter, as well as to characterise the internal structure of organic thin films, porous structures and inclusions within steel. Using time-resolved SANS, growth mechanisms in materials systems and soft matter phase transitions can also be explored. This review is intended for newcomers to SANS as well as experts. Therefore, the basic knowledge required for its use is first summarised. After this introduction, various examples are given of the types of soft and hard matter that have been studied by SANS. The information that can be extracted from the data is highlighted, alongside the methods used to obtain it. In addition to presenting the findings, explanations are provided on how the SANS measurements were optimised, such as the use of contrast variation to highlight specific parts of a structure. Emphasis is placed on the use of complementary techniques to improve data quality (e.g. using other scattering methods) and the accuracy of data analysis (e.g. using microscopy to separately determine shape and size). This is done with a view to providing guidance on how best to design and analyse future SANS measurements on materials not listed below.

Derivatization of fullerene (C-60) with branched aliphatic chains softens C-60-based materials and enables the formation of thermotropic liquid crystals and room temperature nonvolatile liquids. This work demonstrates that by carefully tuning parameters such as type, number and substituent position of the branched chains, liquid crystalline C-60 materials with mesophase temperatures suited for photovoltaic cell fabrication and room temperature nonvolatile liquid fullerenes with tunable viscosity can be obtained. In particular, compound 1, with branched chains, exhibits a smectic liquid crystalline phase extending from 84 degrees C to room temperature. Analysis of bulk heterojunction (BHJ) organic solar cells with a ca. 100 nm active layer of compound 1 and poly(3-hexylthiophene) (P3HT) as an electron acceptor and an electron donor, respectively, reveals an improved performance (power conversion efficiency, PCE: 1.6 + 0.1%) in comparison with another compound, 10 (PCE: 0.5 + 0.1%). The latter, in contrast to 1, carries linear aliphatic chains and thus forms a highly ordered solid lamellar phase at room temperature. The solar cell performance of 1 blended with P3HT approaches that of PCBM/P3HT for the same active layer thickness. This indicates that C-60 derivatives bearing branched tails are a promising class of electron acceptors in soft (flexible) photovoltaic devices.

The power of branched alkyl substituents to alter material properties is known to soft matter chemistry, with examples found in both surfactants and ionic liquids. Here, we highlight their potency in organic molecular/polymeric materials with optoelectronic applications. Attaching branched alkyl chains to the active π-conjugated core modulates core–core interactions and thus softens the material. This can lead to optimised assemblies with improved optoelectronic properties. By increasing the number and volume of the flexible chains, individual cores can be isolated, yielding functional organic liquids with bulk optical properties the same as the intrinsic molecular characteristics obtained for their dilute solutions. These liquid materials can accommodate dopants to offer diverse and tuneable emission colours, and provide an easily applicable flexible and foldable continuous layer for future optoelectronic media.

Nonvolatile room-temperature luminescent molecular liquids are a new generation of organic soft materials. They possess high stability, versatile optical properties, solvent-free fluid behaviour and can effectively accommodate dopant dye molecules. Here we introduce an approach to optimize anthracene-based liquid materials, focussing on enhanced stability, fluorescence quantum yield, colour tunability and processability, with a view to flexible electronic applications. Enveloping the anthracene core in low-viscosity branched aliphatic chains results in stable, nonvolatile, emissive liquid materials. Up to 96% efficient energy-transfer-assisted tunable emission is achieved by doping a minute amount of acceptor dye in the solvent-free state. Furthermore, we use a thermoresponsive dopant to impart thermally controllable luminescence colours. The introduced strategy leading to diverse luminescence colours at a single blue-light excitation can be an innovative replacement for currently used luminescent materials, providing useful continuous emissive layers in developing foldable devices., Nonvolatile luminescent liquids are solvent-free fluids with a range of flexible electronic applications. Here, the authors show that anthracenes enveloped in branched aliphatic compounds are stable emissive liquids, with emissive and thermoresponsive properties that may be tuned by addition of dopants.

Metal oxide/nitride nanocomposites have many existing and potential applications, e.g. in energy conversion or ammonia synthesis. Here, a hybrid oxide/nitride nanocomposite (anatase/TixW1−xN) was synthesized by an ammonia-free sol–gel route. Synchrotron x-ray diffraction, complemented with electron microscopy and thermogravimetric analysis, was used to study the structure, composition and mechanism of formation of the nanocomposite. The nanocomposite contained nanoparticles (

By exploiting spontaneous emulsification to prepare porous SiO(2) particles, we report the formation of porous CeO(2)@SiO(2) hybrid colloids and their incorporation into a silica-zirconia coating to improve the corrosion protection of aluminium.

We report a one-pot route to Au/CeO2 nanocomposites. A readily-available biopolymer, sodium alginate, is exploited for controlled formation and stabilisation of gold nanoparticles followed by in situ growth of a sponge-like network of CeO2 nanoparticles. The flexible nature of this method as a general route to mixed metal/metal oxide nanocomposites is also demonstrated.

New fluorinated microemulsions (F-MEs) formulated from partially fluorinated solvent–co-solvent mixtures and fluorinated anionic AOT-analogue surfactants are reported. These F-MEs permit incorporation of water into fluorinated solvents, up to a volume fraction ϕwater ≈ 0.13. Interestingly, phase behavior and structures, determined by small-angle neutron scattering (SANS), parallel many other classical AOT-type microemulsions, both in normal hydrocarbon and in supercritical-CO2 (scCO2) solvents. Using these new F-MEs as reaction media, F-capped silver nanoparticles (Ag-NPs) have been synthesized, representing the first reported preparation of F-NPs in fluorous phase microemulsions.

Cobalt and nickel salts of the highly branched trichain anionic surfactant sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulfonate (TC14) are shown to be soluble in dense CO(2) at concentrations up to 6 wt % at 500 bar pressure. This is a remarkably high solubility for such hydrocarbon transition metal surfactants in CO(2). High-pressure small-angle neutron scattering (HP-SANS) has been used to study the surfactant aggregates in a normal organic solvent, cyclohexane, dense CO(2), and also mixtures of these two pure solvents. The results show that transition metal TC14 derivatives are viable compounds for incorporating reactive and functional metal ions into CO(2).

Here it is shown that the chemical nature of outer organic surfactant layers, used to stabilize inorganic nanoparticles (NPs), is a key factor controlling solubility in a mixed liquid CO(2)-heptane (10% vol) solvent.

Organosols comprising silica nanoparticles, stabilized by adsorbed surfactant layers in low dielectric organic solvents were formulated, and their properties studied. A range of different methods for organosol formation starting from aqueous sols were evaluated and compared, in order to determine the most reliable and reproducible approach. To understand the influence of surfactant type and solvent on stability, samples were prepared with a range of surfactants and in different solvents and solvent blends. Structural properties and interparticle interactions were probed using dynamic light scattering (DLS), zeta potentials were determined, and the surfactant layers were investigated with contrast-variation SANS. SANS data suggest that for systems stabilized by ionic surfactants, the nanoparticles are in equilibrium with a population of reverse micelles, but this is apparently not the case for those stabilized by nonionic surfactants. Low zeta potentials show evidence of a small amount of surface charging in these nonaqueous systems, although it is unlikely to have any significant effect on their overall stability.

Aggregate structures of two model surfactants, AOT and C12E5 are studied in pure solvents D2O, dioxane-d8 (d-diox) and cyclohexane-d12 (C6D12) as well as in formulated D2O/d-diox and d-diox/C6D12 mixtures. As such these solvents and mixtures span a wide and continuous range of polarities. Small-angle neutron scattering (SANS) has been employed to follow an evolution of the preferred aggregate curvature, from normal micelles in high polarity solvents, through to reversed micelles in low polarity media. SANS has also been used to elucidate the micellar size, shape as well as to highlight intermicellar interactions. The results shed new light on the nature of aggregation structures in intermediate polarity solvents, and point to a region of solvent quality (as characterized by Hildebrand Solubility Parameter, Snyder polarity parameter or dielectric constant) in which aggregation is not favored. Finally these observed trends in aggregation as a function of solvent quality are successfully used to predict the self-assembly behavior of C12E5 in a different solvent, hexane-d14 (C6D14).

Synthesis of nanoparticles in microemulsions is an area of considerable current interest. This subject can be broadly divided into two sections defined by the nature of the host microemulsion reaction medium. Water-in-oil microemulsions have been used to prepare nanoparticles for more than two decades, and a wide variety of materials has been synthesised by these methods. Control parameters have been elucidated for influencing both nanoparticle concentration and morphology, allowing for tailored syntheses with various applications. More recently, the ability to synthesise nanoparticles in water/supercritical fluid microemulsions was realised. This method promises to be a highly useful route for controlled nanoparticle synthesis due to the added control variables afforded by tuneability of the solvent quality (density) through pressure and temperature. This review presents the current state-of-the-art in both fields.

Adsorption and interfacial properties of model methyl-capped nonionic surfactants C8E4OMe [C8H17O(C2H4O)4CH3] and C10E4OMe [C10H21O(C2H4O)4CH3] were studied in water and water/ethylene glycol mixtures as well as pure ethylene glycol. Critical micellar concentrations (cmc's), surface tensions, and surface excess were determined using surface tension (ST) and neutron reflection (NR) as a function of solvent type and surfactant tail length. The ST results show a strong dependence on solvent type in terms of cmc. The NR data were analyzed using a single-layer model for the adsorbed surfactant films. Surprisingly, the adsorption parameters obtained in both water and pure ethylene glycol were very similar, and variations in film thickness or area per molecule are negligible in respect of the uncertainties. Similarly, for C10E4OMe, estimates for the free energies of adsorption and micellization show only a weak solvent dependence. These results suggest that for such model nonionic surfactants dilute solution properties are dictated by solvophobicity, which is quite similar for this class of water, glycol, and water-glycol mixtures. More specifically, the nature of the adsorption layer appears to be hardly affected by the type of solvent subphase. The findings highlight the significance of solvophobicity and show that model nonionic surfactants can behave very similarly in hydrogen-bonding glycol solvents and water.

Nature Chemistry 6, 690–696 (2014); published online 22 June 2014; corrected online 25 June 2014; corrected after print 3 September 2014. In the version of this Article previously published, the fourth co-author's surname was spelt incorrectly, it should have read Sommerdijk. This has been correctedin the online versions of the Article.

One of the biggest challenges for materials science is to design facile routes to structurally complex materials, which is particularly important for global applications such as fuel cells. Doped nanostructured carbons are targeted as noble metal-free electrocatalysts for this purpose. Their intended widespread use, however, necessitates simple and robust preparation methods that do not compromise on material performance. Here, we demonstrate a versatile one-pot synthesis of nitrogen-doped carbons that exploits the templating ability of biological polymers. Starting with just metal nitrates and gelatin, multiphase C/Fe3C/MgO nanomaterials are formed, which are then etched to produce active carbon electrocatalysts with accessible trimodal porosity. These show remarkable performance in the oxygen reduction reaction – a key process in proton exchange membrane fuel cells. The activity is comparable to commercial platinum catalysts and shows improved stability with reduced crossover effects. This simple method offers a new route to widely applicable porous multicomponent nanocomposites.