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A novel butterfly-shaped tetracarboxylic acid [9,9′-methylene-bis(9-methylfluorene-2,7-dicarboxylic acid), H4L] featuring a co-facial bifluorene core was designed and synthesised. Reactions of H4L with CdII produced the luminescent supramolecular frameworks 2 and 3, with different dimensionalities and wingspans of L4−. Their solid-state emission properties were rationalised based on the torsional dynamics of the facing bifluorene units by means of X-ray diffraction analysis and TD-DFT calculations.

We report the results of modelling the transport of n-octane and n-hexadecane and their mixtures through carbonaceous nanopores at high-pressure conditions. Pores are modelled as smooth slit sheets with perturbations added as ridges and steps and a version of the Statistical Associating Fluid Theory (SAFT-γ Mie) is used both as equation of state and as a coarse-grained force field to account for fluid-fluid and fluid-solid molecular interactions. Molecular simulation allowed the description of transport diffusivities in terms of molecular flow, using boundary driven non-equilibrium molecular dynamics (BD-NEMD). Transport diffusivities are also independently calculated using equilibrium and external force non-equilibrium molecular dynamics (EF-NEMD) simulations, after accounting for the adsorption on the pores. We show consistency between the approaches for quantifying transport in terms of permeabilities (Darcy flows) and transport diffusivities. We find that smooth slit carbon pore models, which are commonly employed in literature as surrogates for kerogen regions in shale, are an inadequate representation of ultra-confined natural pores. For slit pores, the flow patterns are characterized by a fully-mutualized plug-like flow and fast transport. However, by incorporating even a small amount of rugosity (roughness) to the solid walls, the diffusion coefficients decrease dramatically with surface roughness significantly affecting the characteristic transport and velocity profiles inside the pores. In all cases, it is seen that there are important cross-correlation effects, influencing the way components of the mixture flow together. Calculated self-diffusivities are orders of magnitude smaller than the observed transport diffusivities for liquid mixtures. This work has a direct impact on the understanding and modelling of unconventional hydrocarbon recovery and flow in organic shale rocks.

Making reliable estimates of gas adsorption in shale remains a challenge because the variability in their mineralogy and thermal maturity results in a broad distribution of pore-scale properties, including size, morphology and surface chemistry. Here, we demonstrate the development and application of a hybrid pore-scale model that uses surrogate surfaces to describe supercritical gas adsorption in shale. The model is based on the lattice Density Functional Theory (DFT) and considers both slits and cylindrical pores to mimic the texture of shale. Inorganic and organic surfaces associated with these pores are accounted for by using two distinct adsorbate-adsorbent interaction energies. The model is parameterised upon calibration against experimental adsorption data acquired on adsorbents featuring either pure clay or pure carbon surfaces. Therefore, in its application to shale, the hybrid lattice DFT model only requires knowledge of the shale-specific organic and clay content. We verify the reliability of the model predictions by comparison against high-pressure CO2 and CH4 adsorption isotherms measured at 40 ◦C in the pressure range 0.01–30 MPa on four samples from three distinct plays, namely the Bowland (UK), Longmaxi (China) and Marcellus shale 1 (USA). Because it uses only the relevant pore-scale properties, the proposed model can be applied to the analysis of other shales, minimising the heavy experimental burden associated with high pressure experiments. Moreover, the proposed development has general applicability meaning that the hybrid lattice DFT can be used to the characterisation of any adsorbent featuring morphologically and chemically heterogeneous surfaces.

A new method that utilizes theories of thermally activated deformation and repeated transient stress-relaxation tests has been proposed and validated in this study for the characterization and modeling of the stress-relaxation aging (SRA) behavior of aluminum alloys and its dependence on stress and temperature. Using the new method, key deformation-related variables, i.e., stress components, activation volume, and activation energy, of the aerospace grade heat-treatable aluminum alloy AA7B04 have been obtained as a function of aging temperature (388 K, 413 K and 438 K), stress (both elastic and plastic), and SRA time (up to 4 hours). It has been found that the apparent activation energy Qa of the material remains constant in the elastic region but decreases with the increase in strain in the plastic region, and also decreases with the increase in temperature for all initial loading stresses. These characteristics contribute to a much higher degree of stress relaxation in the plastic region and at higher temperatures than in the elastic region and/or at lower temperatures. The obtained changing activation volume V and Qa indicate that the deformation rate is controlled by forest dislocation interactions in the elastic region (V decreases from over 200b3 to less than 100b3), and by a cross-slip mechanism at high stress levels in the plastic region (V decreases to a few tens of b3). Based on these theories and results, a novel and simple constitutive model has been proposed, with which the stress-relaxation behavior of AA7B04 at different aging temperatures (388 K to 448 K), preloaded from elastic to plastic regions for up to 16 hours has been successfully predicted. The proposed model eliminates the limitations of conventional SRA models which mainly deals with elastic loading and isothermal conditions, and provides a foundation to effectively predict the springback after advanced non-isothermal SRA forming of aluminum alloy structures in the aerospace industry.

Circularly polarized organic light-emitting diodes (CP-OLEDs) that demonstrate both state-of-the-art efficiency and strongly circularly polarized (CP) electroluminescence have proved a considerable technical challenge. Furthermore, multiple factors – from film thickness to device structure – have been shown to influence the sign of the emitted CP light, independent of the handedness (absolute stereochemistry) of the chiral emitter. Here we report CP-OLEDs using a blend of poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) and a chiral small molecule additive (1-aza[6]helicene, aza[6]H). We demonstrate CP-OLEDs with an impressive electroluminescence dissymmetry (gEL) > 0.3 and a current efficiency of 0.53 cd A−1 and brightness of 3023 cd m−2. While at low aza[6]H loadings, F8T2 blends are consistent with previous observations of CP dissymetric inversion as a function of film thickness/excitation mode, a higher loading of aza[6]H (∼40 wt%) removes such dependencies while retaining excellent g-factors. The materials disclosed will allow for further mechanistic studies of chiral polymeric materials and provide new opportunities for chiroptical optimisation in films and devices.

Environmental stability remains a major challenge for the commercialisation of organic solar cells and degradation pathways remain poorly understood. Designing materials for improved device stability requires an understanding of the relationship between the properties of the donor or acceptor molecule and different degradation mechanisms. Here we study the correlations between various molecular parameters of the fullerene derivative bis-PCBM and the degradation rate of polymer:bis-PCBM organic solar cells, based on the same carbazole-alt-benzothiadiazole polymer, in aerobic and anaerobic conditions. We compare eight high purity bis-PCBM isomers with different electronic, chemical and packing properties along with PCBM and the mixture of bis isomers. In the case of aerobic photodegradation, we find that device degradation rate is positively correlated to the LUMO energy of the bis-PCBM isomer and to the degree of crystallinity of the isomer, while the correlation of degradation with driving force for epoxide formation is unclear. These results support the idea that in these samples, aerobic photodegradation proceeds via superoxide formation by the photogenerated polaron on the fullerene, followed by further chemical reaction. In the absence of air, photodegradation rate is correlated with molecular structure, supporting the mechanism of microstructural degradation via fullerene dimerization. The approach and findings presented here show how control of specific molecular parameters through chemical design can serve as a strategy to enhance stability of organic solar cells.

In the last couple of decades, researchers have been working on Ruddlesden-Popper phases to realise them as components of solid oxide cells. Ruddlesden-Popper phase materials have been particularly proposed as materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). As such a sizeable literature was produced on Ruddlesden-Popper phases and in this short review we look at these studies with a particular focus on the structural chemistry, oxygen transport and electrical conductivity, electrochemical performance, and stability of these materials under operating conditions. More specifically, the materials have been studied for cathodes and, therefore, we believe a review dedicated to cathode applications of these materials will be beneficial for the community. A brief outlook on the future directions in the field will also be provided.

Improved methods are presented for the separation of platinum from iron meteorites and subsequent analyses of both mass-independent and mass-dependent Pt isotope compositions of iron meteorites by multiple collector ICP-MS. The procedures are optimised for sample throughput and feature improvements in yield and the reduction of constituents that produce spectral interferences and matrix effects. The performance of the methods is demonstrated by replicate analyses of terrestrial reference materials and eight iron meteorites from the IC and IVB groups. The pilot iron meteorite analyses confirm previous work, which demonstrates that the Pt isotope compositions of iron meteorites are particularly sensitive to alteration by neutron capture reactions induced by exposure to galactic cosmic rays (GCR). It is shown that the mass-independent Pt isotope data obtained with the new methods are suitable for accurate correction of correlated cosmogenic isotope effects for other isotope systems in the same sample aliquots. The methods for the measurement of mass-dependent Pt isotope compositions (δ198Pt) employ a robust double spike approach. The accurate determination of δ198Pt values for iron meteorites requires, however, that possible cosmogenic isotope effects from GCR exposure are monitored and appropriately corrected on a sample aliquot specific basis. A robust approach for such corrections using the mass-independent Pt isotope data collected with the new methods is shown to provide accurate results for iron meteorites with variable compositions and GCR exposure histories. Initial results obtained for eight IC and IVB iron meteorites reveal both within- and between-group variations in δ198Pt values, which indicate that such analyses may provide novel constraints for studies of planetary processes.

Self-doping organic semiconductors provide a promising route to avoid instabilities and morphological issues associated with molecular n-type dopants. Structural characterization of a naphthalenetetracarboxylic diimide (NDI) semiconductor covalently bound to an ammonium hydroxide group is presented. The dopant precursor was found to be the product of an unexpected base catalyzed hydrolysis, which was reversible. The reversible hydrolysis had profound consequences on the chemical composition, morphology, and electronic performance of the doped films. In addition, we investigated the degradation mechanism of the quaternary ammonium group and the subsequent doping of NDI. These findings reveal that the products of more than one chemical reaction during processing of films must be considered when utilizing this promising class of water-soluble semiconductors.

Water pollution is considered a serious threat to human life. An advanced oxidation process in the presence of semiconductor photocatalysts is a popular method for the effective decomposition of organic pollutants from wastewater. TiO2 nanoparticles are widely used as photocatalysts due to their low cost, chemical stability, environmental compatibility and significant efficiency. The aim of this study is to review the photocatalytic processes and their mechanism, reaction kinetics, optical and electrical properties of semiconductors and unique characteristics of titanium as the most widely used photocatalyst; and to compare the photocatalytic activity between different titania phases (anatase, rutile, and brookite) and between colorful and white TiO2 nanoparticles. Photocatalytic processes are based on the creation of electron–hole pairs. Therefore, increasing stability and separation of charge carriers could improve the photocatalytic activity. The synthesis method has a significant effect on the intensity of photocatalytic activity. The increase in the density of surface hydroxyls as well as the significant mobility of the electron–hole pairs in the anatase phase increases its photocatalytic activity compared to other phases. Electronic and structural changes lead to the synthesis of colored titania with different photocatalytic properties. Among colored titania materials, black TiO2 showed promising photocatalytic activity due to the formation of surface defects including oxygen vacancies, increasing the interaction with the light irradiation and the lifetime of photogenerated electron–hole pairs. Among non-metal elements, nitrogen doping could be effectively used to drive visible light-activated TiO2.

Two ingots weighing 400 g and 5 kg with nominal compositions of Fe–8Mn–4Al–2Si–0.5C–0.07V–0.05Sn were produced to investigate the effect of processing variables on microstructure development. The larger casting has a cooling rate more representative of commercial production and provides an understanding of the potential challenges arising from casting-related segregation during efforts to scale up medium Mn steels, while the smaller casting has a high cooling rate and different segregation pattern. Sections from both ingots were homogenized at 1250 $$^{\circ} $$ ∘ C for various times to study the degree of chemical homogeneity and $$\delta $$ δ -ferrite dissolution. Within 2 hours, the Mn segregation range (max–min) decreased from 8.0 to 1.7 wt pct in the 400 g ingot and from 6.2 to 1.5 wt pct in the 5 kg ingot. Some $$\delta $$ δ -ferrite also remained untransformed after 2 hours in both ingots but with the 5 kg ingot showing nearly three times more than the 400 g ingot. Micress modeling was carried out, and good agreement was seen between predicted and measured segregation levels and distribution. After thermomechanical processing, it was found that the coarse untransformed $$\delta $$ δ -ferrite in the 5 kg ingot turned into coarse $$\delta $$ δ -ferrite stringers in the finished product, resulting in a slight decrease in yield strength. Nevertheless, rolled strips from both ingots showed $$>900$$ > 900 MPa yield strength, $$>1100$$ > 1100 MPa tensile strength, and $$>40$$ > 40 pct elongation with $$ < 10 pct difference in strength and no change in ductility when compared to a fully homogenized sample.

Following the successful introduction of two benign solvents for cleaving protected acid peptide fragments from 2-chlorotrityl chloride (2-CTC) resin, there is a need to green the cleavage process for obtaining protected peptide amide fragments. In this work, p-xylene and toluene are introduced as greener alternates to dichloromethane (DCM) for preparing protected peptide amide fragments from a Sieber amide resin. The N-dealkylation is a demanding chemical reaction, requiring that the cleavage protocol be optimised to ensure complete cleavage from the resin. After a 30 min reaction time, only 66 % of the final peptide product was retrieved even with the conventional dichloromethane solvent. Therefore, 120 min was considered sufficient to fully cleave the peptide from the Sieber amide resin. This work reaffirms the fact that greening strategies are far from detrimental, with green alternatives often outperforming their replaced counterparts.

Process optimisation and reaction kinetic model development were carried out for two-stage esterification-transesterification reactions of waste cooking oil (WCO) biodiesel. This study focused on these traditional processes due to their techno-economic feasibility, which is an important factor before deciding on a type of feedstock for industrialisation. Four-factor and two-level face-centred central composite design (CCD) models were used to optimise the process. The kinetic parameters for the esterification and transesterification processes were determined by considering both pseudo-homogeneous irreversible and pseudo-homogeneous first-order irreversible processes. For the esterification process, the optimal conditions were found to be an 8.12:1 methanol to oil molar ratio, 1.9 wt.% of WCO for H2SO4, and 60 °C reaction temperature for a period of 90 min. The optimal process conditions for the transesterification process were a 6.1:1 methanol to esterified oil molar ratio, 1.2 wt.% of esterified oil of KOH, reaction temperature of 60 °C, and a reaction time of 110 min in a batch reactor system; the optimal yield was 99.77%. The overall process conversion efficiency was found to be 97.44%. Further research into reaction kinetics will aid in determining the precise reaction process kinetic analysis in future.

Studying the effects of UV and VUV radiation on non‐canonical DNA/RNA nucleobases allows us to compare how they release excess energy following absorption with respect to their canonical counterparts. This has attracted much research attention in recent years because of its likely influence on the origin of our genetic lexicon in prebiotic times. Here we present a CASSCF and XMS‐CASPT2 theoretical study of the photoionisation of non‐canonical pyrimidine nucleobase isocytosine in both its keto and enol tautomeric forms. We analyse their lowest energy cationic excited states including 2π+ , 2nO+ and 2nN+ and compare these to the corresponding electronic states in cytosine. Investigating lower‐energy decay pathways we find – unexpectedly ‐ that keto‐isocytosine+ presents a sizeable energy barrier potentially inhibiting decay to its cationic ground state, whereas enol‐isocytosine+ features a barrierless and consequently ultrafast pathway analogous to the one previously found for the canonical (keto) form of cytosine+. Dynamic electron correlation reduces the energy barrier in the keto form substantially (by ∼1 eV) but it is nevertheless still present. We additionally compute the UV/Vis absorption signals of the structures encountered along these decay channels to provide spectroscopic fingerprints to assist future experiments in monitoring these intricate photo‐processes., The photostability of isocytosine upon ionising radiation exposure is assessed theoretically in both keto and enol tautomeric forms. This non‐canonical base, which features analogous UV excited state reactivity to DNA nucleobase cytosine, unexpectedly displays sizeable energy barriers along the cationic excited state in its keto form that hamper the decay. Simulations suggest isocytosine is less photostable against photoionisation, a factor that might contribute to selecting the more resilient cytosine under prebiotic VUV radiation exposure.

CO2 electroreduction powered by renewable electricity represents a promising method to enclose anthropogenic carbon cycle. Current catalysts display high selectivity toward the desired product only over a narrow potential window due primarily to unoptimized intermediate binding. Here, we report a functional ligand modification strategy in which palladium nanoparticles are encapsulated inside metal–organic frameworks with 2,2′-bipyridine organic linkers to tune intermediate binding and thus to sustain a highly selective CO2-to-CO conversion over widened potential window. The catalyst exhibits CO faradaic efficiency in excess of 80% over a potential window from −0.3 to −1.2 V and reaches the maxima of 98.2% at −0.8 V. Mechanistic studies show that the 2,2′-bipyridine on Pd surface reduces the binding strength of both *H and *CO, a too strong binding of which leads to competing formate production and CO poison, respectively, and thus enhances the selectivity and stability of CO product.

C-C chemokine receptor 5 (CCR5) is a major co-receptor molecule used by HIV-1 to enter cells. Two X-ray crystallographic studies are presented of the antibody RoAb13, which binds to the peptide PIYDIN, which is part of the N-terminal domain of CCR5. The results may provide the basis for active immunization vaccines to stimulate an antibody response to native CCR5 that will block HIV infection., C-C chemokine receptor 5 (CCR5) is a major co-receptor molecule used by HIV-1 to enter cells. This led to the hypothesis that stimulating an antibody response would block HIV with minimal toxicity. Here, X-ray crystallographic studies of the anti-CCR5 antibody RoAb13 together with two peptides were undertaken: one peptide is a 31-residue peptide containing the PIYDIN sequence and the other is the PIDYIN peptide alone, where PIYDIN is part of the N-terminal region of CCR5 previously shown to be important for HIV entry. In the presence of the longer peptide (the complete N-terminal domain), difference electron density was observed at a site within a hypervariable CDR3 binding region. In the presence of the shorter core peptide PIYDIN, difference electron density is again observed at this CDR3 site, confirming consistent binding for both peptides. This may be useful in the design of a new biomimetic to stimulate an antibody response to CCR5 in order to block HIV infection.

Low salinity water flooding is a promising enhanced oil recovery technique that has been observed, in experiments over a range of scales, to increase oil production by up to 14% in some systems. However, there is still no way of reliably predicting which systems will respond favourably to the technique. This shortcoming is partly because of a relative lack of pore scale observations of low salinity water flooding. This has led to a poor understanding of how mechanisms on the scale of micrometres lead to changes in fluid distribution on the scale of centimetres to reservoir scales. In this work, we use X-ray micro-CT scanning to image unsteady state experiments of tertiary low salinity water flooding in Berea, Castlegate, and Bunter sandstone micro-cores. We observe fluid saturations and characterise the wetting state of samples using imagery of fluid–solid fractional wetting and pore occupancy analysis. In the Berea sample, we observed an additional oil recovery of 3 percentage points during low salinity water flooding, with large volumes of oil displaced from small pores but also re-trapping of mobilised oil in large pores. In the Bunter sandstone, we observed 4 percentage point additional recovery with significant displacement of oil from small pores and no significant retrapping of oil in large pores. However, in the Castlegate sample, we observed just 1 percentage point of additional recovery and relatively small volumes of oil mobilisation. We observe a significant wettability alteration towards more water-wet conditions in the Berea and Bunter sandstones, but no significant alteration in the Castlegate sample. We hypothesise that pore structure, specifically the topology of large pores impacted recovery. We find that poor connectivity of the largest pores in each sample is strongly correlated to additional recovery. This work is the first systematic comparison of the pore scale response to low salinity flooding across multiple sandstone samples. Moreover, it gives the first pore scale insights into the role of pore geometry and topology on the mobilisation of oil during low salinity water flooding.

The permeability of the intestinal barrier is altered in a multitude of gastrointestinal conditions such as Crohn’s and coeliac disease. However, the clinical utility of gut permeability is currently limited due to a lack of reliable diagnostic tests. To address this issue, we report a novel technique for rapid, non-invasive measurement of gut permeability based on transcutaneous (‘through-the-skin’) fluorescence spectroscopy. In this approach, participants drink an oral dose of a fluorescent dye (fluorescein) and a fibre-optic fluorescence spectrometer is attached to the finger to detect permeation of the dye from the gut into the blood stream in a non-invasive manner. To validate this technique, clinical trial measurements were performed in 11 healthy participants. First, after 6 h of fasting, participants ingested 500 mg of fluorescein dissolved in 100 ml of water and fluorescence measurements were recorded at the fingertip over the following 3 h. All participants were invited back for a repeat study, this time ingesting the same solution but with 60 g of sugar added (known to transiently increase intestinal permeability). Results from the two study datasets (without and with sugar respectively) were analysed and compared using a number of analysis procedures. This included both manual and automated calculation of a series of parameters designed for assessment of gut permeability. Calculated values were compared using Student’s T-tests, which demonstrated significant differences between the two datasets. Thus, transcutaneous fluorescence spectroscopy shows promise in non-invasively discriminating between two differing states of gut permeability, demonstrating potential for future clinical use.

Iron is a common impurity in magnesium alloys, and is acknowledged to accelerate Mg corrosion, contributing to Mg’s poor corrosion resistance. However, an atomistic understanding of this acceleration effect is still incomplete. Here we use Density Functional Theory simulations performed with the Quantum Espresso package to investigate several Fe/Mg models, calculating the associated work functions, atomic charges, and H and Fe absorption energies. Compared with a pure Mg slab, we find that Fe’s existence increases the work function and decreases the H adsorption energy. Furthermore, a general trend is observed that the Fe absorption energy decreases with increasing interaction between Fe atoms on the Mg substrate. Based on these results, a mechanism based on charge redistribution is put forward to explain how Fe accelerates the corrosion of Mg. Our findings provide insight into Mg’s corrosion process at the atomic level that might inform future measures to prevent corrosion.

The mesostructure of porous electrodes used in lithium-ion batteries strongly influences cell performance. Accurate imaging of the distribution of phases in these electrodes would allow this relationship to be better understood through simulation. However, imaging the nanoscale features in these components is challenging. While scanning electron microscopy is able to achieve the required resolution, it has well established difficulties imaging porous media. This is because the flat imaging planes prepared using focused ion beam milling will intersect with the pores, which makes the images hard to interpret as the inside walls of the pores are observed. It is common to infiltrate porous media with resin prior to imaging to help resolve this issue, but both the nanoscale porosity and the chemical similarity of the resins to the battery materials undermine the utility of this approach for most electrodes. In this study, a technique is demonstrated which uses in situ infiltration of platinum to fill the pores and thus enhance their contrast during imaging. Reminiscent of the Japanese art of repairing cracked ceramics with precious metals, this technique is referred to as the kintsugi method. The images resulting from applying this technique to a conventional porous cathode are presented and then segmented using a multi-channel convolutional method. We show that while some cracks in active material particles were empty, others appear to be filled (perhaps with the carbon binder phase), which will have implications for the rate performance of the cell. Energy dispersive X-ray spectroscopy was used to validate the distribution of phases resulting from image analysis, which also suggested a graded distribution of the binder relative to the carbon additive. The equipment required to use the kintsugi method is commonly available in major research facilities and so we hope that this method will be rapidly adopted to improve the imaging of electrode materials and porous media in general.

Multi-axial compression of the mushy zone occurs in various pressurized casting processes. Here, we present a drained triaxial compression apparatus for semi-solid alloys that allow liquid to be drawn into or expelled from the sample in response to isotropic or triaxial compression. The rig is used to measure the pressure-dependent flow stress and volumetric response during isothermal triaxial compression of globular semi-solid Al-15 wt pct Cu at 70 to 85 vol pct solid. Analysis of the stress paths and the stress–volume data show that the combination of the solid fraction and mean effective pressure determines whether the material undergoes shear-induced dilation or contraction. The results are compared with the critical state soil mechanics (CSSM) framework and the similarities and differences in behavior between equiaxed semi-solid alloys and soils are discussed.

Lubricant-infused surfaces (LIS) have emerged as an innovative way to combat several modern challenges such as biofouling, ice formation, and surface drag. The favorable properties of LIS are dependent on the presence and distribution of a lubricant layer coating the underlying substrate. Unfortunately, this layer is not indefinitely stable and depletes due to external forces. Here, we study how an air/water interface depletes the lubricant from LIS as a function of lubricant wettability on the substrate by varying the chemistry of both the lubricant and the substrate. The lubricants were chosen to represent some of those most commonly used in the literature (silicone oil, perfluoropolyethers, and mineral oil). We use an optical Wilhelmy plate tensiometer to measure the contact angle of the air/water interface on the LIS in situ as the sample is driven through the air/water interface and contact angle hysteresis as a qualitative measure of lubricant depletion. This data is augmented with ex situ quantitative mapping of lubricant thickness using atomic force microscopy (AFM) meniscus force measurements. We find that a thick layer of excess lubricant is always removed in just one dip, regardless of wettability, and that lubricants that do not spread fully on the substrate deplete faster due to their dewetting into droplets. We also find that lubricants that spread onto the air/water interface are more susceptible to depletion. Finally, we investigate the effect of repeated immersions on the properties of liquid-like poly(dimethylsiloxane) (PDMS) chains tethered to glass and find that dynamic contact angles on these surfaces remain constant over several dips and therefore their low hysteresis is unlikely due to unbound polymer.

Using a theoretical method which employs equilibration between the cohesive and destructive energies of a crystal, it is shown that protein layers of monomolecular thickness formed in pores can grow into macroscopic crystals. Experimental studies, stimulated from theoretical considerations, widen the palette of porous materials that can promote protein crystallization., The nucleation ability of pores is explained using the equilibration between the cohesive energy maintaining the integrity of a crystalline cluster and the destructive energy tending to tear it up. It is shown that to get 3D crystals it is vital to have 2D crystals nucleating in the pores first. By filling the pore orifice, the 2D crystal nuclei are more stable because their peripheries are protected from the destructive action of water molecules. Furthermore, the periphery of the 2D crystal is additionally stabilized as a result of its cohesion with the pore wall. The understanding provided by this study combining theory and experiment will facilitate the design of new nucleants.

In the search for high performance n-type organic semiconductors (OSCs) a simple strategy might be substitution of aromatic CH groups for nitrogen heteroatoms. Here, we report the synthesis and characterisation of two novel N-heteroacene compounds, namely, 1,5,12-triazatetracene (TrAT1) and 2,5,12-triazatetracene (TrAT2). Their potential as n-type materials is evaluated against 5,12-diazatetracene (DAT) by UV/vis and EPR spectroscopy, cyclic voltammetry, DFT, single crystal X-ray diffraction and thin film characterisation. Increasing the number of N-heteroatoms was found to stabilise the HOMO and LUMO leading to electron affinities for TrAT1 and TrAT2 of ca. −4 eV. Both compounds were found to exhibit columns of co-facial π-stacked molecules. For TrAT1, molecules are also linked by hydrogen bonding, while the crystal structure of TrAT2 was found to be inherently disordered. Thin films of DAT, TrAT1 and TrAT2 were grown by organic molecular beam deposition (OMBD) and found to form discontinuous films, where TrAT1 exhibited a preferential orientation.

Polymorphic nucleation behavior of carbamazepine (CBZ) was investigated in terms of supersaturation in several solvents: nitromethane, acetonitrile, acetone, ethanol, 2-propanol and toluene. The solubility was measured and the effects of interaction between the solvent and CBZ on solubility and polymorphic nucleation were discussed. It was found that the polymorphic forms of CBZ largely depended on the solvent type and supersaturation ratio. The carbonyl group in acetone blocked the NH⋯O interaction between the dimer in form II by mimicking the same interaction with CBZ, then favored the nucleation of form III. The aromatic–aromatic interaction between CBZ and the solvent like toluene decreased the solute–solute interaction and favored the formation of form II. The nucleation domains of CBZ polymorphs (forms II and III) were separated as a function of supersaturation ratio range in each solvent, and the effects of solvents and supersaturation ratios on the induction time and transformation process were also explored. The interfacial energies of forms II and III in different solvents were calculated, and it was found that, at all investigated supersaturation ratios, the interfacial energy of form II in all solvents except acetone was always lower than that of form III, indicating that nucleation kinetics preferably favored the formation of form II. However, at lower supersaturation ratios, thermodynamics was critical and form III was obtained.

The electrochemical reduction of carbon dioxide (CO2) to chemicals is gaining great attention as a pragmatic solution for greenhouse gas mitigation and for the utilization of CO2 to produce useful fuels and chemical feedstocks using intermittent renewable energy sources. In recent years, strategies to design electrocatalysts for CO2 reduction to ethanol, a valuable liquid fuel, have been increasingly reported. The mechanistic understanding providing insights into steps of the reduction process has allowed for further development of highly efficient and selective catalysts. Several significant breakthroughs have been made; however, the door toward industrial-scale production of ethanol from CO2 is still wide open as most electrocatalytic systems reported so far are still suffering from low energy efficiency, inferior stability, and discouraging selectivity. Inspired by recent advances in the field, we herein provide a review of fundamental and material advances of the electrochemical CO2 reduction to ethanol. First, we discuss the pathways and the effects of reaction-environment factors on the formation of ethanol from both theoretical and spectroscopic points of view. We then give an overview of different strategies to design electrocatalysts for this reaction. Finally, we discuss the remaining challenges and propose promising future research directions, with the aim to bring this technology closer to practical applications.

To realise the promise of solid-state batteries, negative electrode materials exhibiting large volumetric expansions, such as Li and Si, must be used. These volume changes can cause significant mechanical stresses and strains that affect cell performance and durability, however their role and nature in SSBs are poorly understood. Here, a 2D electro-chemo-mechanical model is constructed and experimentally validated using steady-state, transient and pulsed electrochemical methods. The model geometry is taken as a representative cross-section of a non-porous, thin-film solid-state battery with an amorphous Si (a-Si) negative electrode, lithium phosphorous oxynitride (LiPON) solid electrolyte and LiCoO2 (LCO) positive electrode. A viscoplastic model is used to predict the build-up of strains and plastic deformation of a-Si as a result of (de)lithiation during cycling. A suite of electrochemical tests, including electrochemical impedance spectroscopy, the galvanostatic intermittent titration technique and hybrid pulse power characterisation are carried out to establish key parameters for model validation. The validated model is used to explore the peak interfacial (a-Si∣LiPON) stress and strain as a function of the relative electrode thickness (up to a factor of 4), revealing a peak volumetric expansion from 69% to 104% during cycling at 1C. The validation of this electro-chemo-mechanical model under load and pulsed operating conditions will aid in the cell design and optimisation of solid-state battery technologies.

We developed a polymer–drug strategy to explore anticancer polymers. A series of monomers containing groups with potential anticancer activity have been facilely prepared through the Biginelli reaction. These monomers were used to produce water-soluble polymers through convenient radical copolymerization. The resulting polymers are biocompatible and can be directly used to suppress proliferation of different cancer cells without the release of small molecules. Theoretical calculations revealed that Biginelli groups in polymers had strong interaction with the Eg5 protein, which is highly expressed in cancer cells and is closely related to cell mitosis. Subsequent cell experiments confirmed that a screened polymer is efficient in inhibiting mitosis in different cancer cells. Our study of exploring functional polymers via the combination of multicomponent reactions and theoretical calculation resulted in promising anticancer polymers, which might pave a path for de novo designing of functional polymers and have important implications in the fields of organic, computational, and polymer chemistry.

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.

New approaches for enhanced oil recovery (EOR) with a reduced environmental footprint are required to improve recovery from mature oil fields, and when combined with carbon capture and storage (CCS) can provide useful options for resource maximisation during the net zero transition. Electrical heating is investigated as a potential EOR method in carbonate reservoirs. Samples were placed in an apparatus surrounded by a wire coil across which different DC (direct current) voltages were applied. Monitoring the imbibition of both deionized water (DW) and seawater (SW) into initially oil-wet Austin chalk showed that water imbibed into the rock faster when heated in the presence of a magnetic field. This was associated with a reduction in the water–air contact angle over time measured on the external surface of the sample. Without heating, the contact angle reduced from 127° approaching water-wet conditions, 90°, in 52 min, while in the presence of heating with 3 V, 6 V, and 9 V applied across a sample 17 mm in length, the time required to reach the same contact angle was only 47, 38 and 26 min, respectively, while a further reduction in contact angle was witnessed with SW. The ultimate recovery factor (RF) for an initially oil-wet sample imbibed by DW was 13% while by seawater (SW) the recorded RF was 26% in the presence of an electrical heating compared with 2.8% for DW and 11% for SW without heating. We propose heating as an effective way to improve oil recovery, enhancing capillary-driven natural water influx, and observe that renewable-powered heating for EOR with CCS may be one option to improve recovery from mature oil fields with low environmental footprint.

Semi‐implantable needle oxygen electrodes were used for forearm subcutaneous monitoring in human subjects undertaking high intensity cycling and fist clenching exercise. pO2 variations in the range between 40 and 100 mm Hg oxygen were seen. Superimposed on these were paradoxical rises in subcutaneous pO2, of up to 100 mm Hg which paralleled the scale of the exercise. This was indicative of increased blood flow through skin. Triton X‐100 incorporated into the sensor polyurethane membranes helped to give faster responses and reduced the possibility of biofouling and drift. The sterilizable system, free from internal electrolyte film appears promising for future clinical monitoring.

Two different octadentate gadolinium chelates based on DO3A and DOTAGA chelates (hydration number q = 1) have been used to prepare a series of bi-, tri-, and tetrametallic d–f mixed-metal complexes. The piperazine-based dithiocarbamate linker ensures that rotation of the gadolinium chelates is restricted, leading to enhanced relaxivity (r1) values, which increase with the overall mass and number of gadolinium units. The r1 value (at 10 MHz, 25 °C) per gadolinium unit rises from 5.0 mM–1 s–1 for the Gd-DO3A-NH2 monogadolinium chelate to 9.2 mM–1 s–1 in a trigadolinium complex with a ruthenium(III) core. Using a 1.5 T clinical scanner operating at 63.87 MHz (25 °C), an 86% increase in the relaxivity per gadolinium unit is observed for this multimetallic compound compared to clinically approved Dotarem. The gadolinium complexes based on the DOTAGA chelate also performed well at 63.87 MHz, with a relaxivity value of 9.5 mM–1 s–1 per gadolinium unit being observed for the trigadolinium d–f mixed-metal complex with a ruthenium(III) core. The versatility of dithiocarbamate coordination chemistry thus provides access to a wide range of d–f hybrids with potential for use as high-performance MRI contrast agents.

Single-molecule pulling experiments are widely used to extract both thermodynamic and kinetic data on ligand-receptor pairs, typically by fitting different models to the probability distribution of rupture forces of the corresponding bond. Here, a theoretical model is presented that shows how a measurement of the number of binding and unbinding events as a function of the observation time can also give access to both the binding (kon) and the unbinding (koff) rates of bonds, which combined provide a well-defined bond free-energy ΔGbond. The connection between ΔGbond and the ligand-receptor binding constant measured by typical binding essays is critically discussed. The role played by the molecular construct used to tether ligands and receptors to a surface is considered, highlighting the various approximations necessary to derive general expressions that connect its structure to its contribution, termed ΔGcnf, to the bond free-energy. In this way, the validity and the assumptions underpinning widely employed formulas and experimental protocols used to extract binding constants from single-molecule experiments are assessed. Finally, the role of ΔGcnf in processes mediated by ligand-receptor binding is briefly considered, and an experiment to unambiguously measure this quantity proposed.

Aβ4–42 is the major subspecies of Aβ peptides characterized by avid Cu(II) binding via the ATCUN/NTS motif. It is thought to be produced in vivo proteolytically by neprilysin, but in vitro experiments in the presence of Cu(II) ions indicated preferable formation of C-terminally truncated ATCUN/NTS species including CuIIAβ4–16, CuIIAβ4–9, and also CuIIAβ12–16, all with nearly femtomolar affinities at neutral pH. Such small complexes may serve as shuttles for copper clearance from extracellular brain spaces, on condition they could survive intracellular conditions upon crossing biological barriers. In order to ascertain such possibility, we studied the reactions of CuIIAβ4–16, CuIIAβ4–9, CuIIAβ12–16, and CuIIAβ1–16 with reduced glutathione (GSH) under aerobic and anaerobic conditions using absorption spectroscopy and mass spectrometry. We found CuIIAβ4–16 and CuIIAβ4–9 to be strongly resistant to reduction and concomitant formation of Cu(I)–GSH complexes, with reaction times ∼10 h, while CuIIAβ12–16 was reduced within minutes and CuIIAβ1–16 within seconds of incubation. Upon GSH exhaustion by molecular oxygen, the CuIIAβ complexes were reformed with no concomitant oxidative damage to peptides. These finding reinforce the concept of Aβ4–x peptides as physiological trafficking partners of brain copper., Aβ4−16, Aβ4−9, and Aβ12−16, oligopeptide products of β-amyloid degradation by neprilysin, bind CuII ions very tightly and are considered as possible CuII carriers in the brain. We demonstrated that CuII(Aβ4−x) complexes, but not CuII(Aβ12−16), are kinetically resistant to reduction by glutathione. No covalent Aβ peptide modifications were observed during the copper reduction and reoxidation by ambient oxygen, yielding the original complexes. These features suggest that CuII(Aβ4−x) complexes might be able to cross the blood−brain barrier.

Determining stability constants of uranyl complexes with the principal functional groups in siderophores and identifying stability series is of great importance to predict which siderophore classes preferentially bind to UVI and, hence, impact uranium speciation in the environment. It also helps to develop resins for scavenging UVI from aqueous solutions. Here, we apply a recently developed computational approach to calculate log β values for a set of geochemically relevant uranium organometallic complexes using Density Functional Theory (DFT). We determined the stability series for catecholate, hydroxamate, α-hydroxycarboxylate, α-aminocarboxylate, hydroxy-phenyloxazolonate, and α-hydroxyimidazole with the uranyl cation. In this work, the stability constants (log β110) of α-hydroxyimidazolate and hydroxy-phenyloxazolonate are calculated for the first time. Our approach employed the B3LYP density functional approximation, aug-cc-pVDZ basis set for ligand atoms, MDF60 ECP for UVI, and the IEFPCM solvation model. DFT calculated log β110 were corrected using a previously established fitting equation. We find that the siderophore functional groups stability decreases in the order: α-hydroxycarboxylate bound via the α-hydroxy and carboxylate groups (log β110 = 17.08), α-hydroxyimidazolate (log β110 = 16.55), catecholate (log β110 = 16.43), hydroxamate (log β110 = 9.00), hydroxy-phenyloxazolonate (log β110 = 8.43), α-hydroxycarboxylate bound via the carboxylate group (log β110 = 7.51) and α-aminocarboxylate (log β110 = 4.73). We confirm that the stability for the binding mode of the functional groups decrease in the order: bidentate, monodentate via ligand O atoms, and monodentate via ligand N atoms. The stability series strongly suggests that α-hydroxyimidazolate is an important functional group that needs to be included when assessing uranyl mobility and removal from aqueous solutions.

Efficient photomolecular motors will be critical elements in the design and development of molecular machines. Optimisation of the quantum yield for photoisomerisation requires a detailed understanding of molecular dynamics in the excited electronic state. Here we probe the primary photophysical processes in the archetypal first generation photomolecular motor, with sub‐50 fs time resolved fluorescence spectroscopy. A bimodal relaxation is observed with a 100 fs relaxation of the Franck‐Condon state to populate a red‐shifted state with a reduced transition moment, which then undergoes multi‐exponential decay on a picosecond timescale. Oscillations due to the excitation of vibrational coherences in the S1 state are seen to survive the ultrafast structural relaxation. The picosecond relaxation reveals a strong solvent friction effect which is thus ascribed to torsion about the C−C axle. This behaviour is contrasted with second generation photomolecular motors; the principal differences are explained by the existence of a barrier on the excited state surface in the case of the first‐generation motors which is absent in the second generation. These results will help to provide a basis for designing more efficient molecular motors in the future., Generation conflict? The excited state dynamics of first‐generation molecular motors are studied by means of ultrafast time resolved fluorescence. A 100 fs structural reorganization in the excited state is followed by a slower excited state relaxation, which is influenced by solvent viscosity. The decay is accompanied by coherent vibrational excitation of modes in the excited electronic state. The observed behaviour is contrasted with that of the second‐generation motors.

In situ quick extended X-ray absorption fine structure spectroscopy (QEXAFS) was employed to study temporally and spatially the leaching of Pd from a heterogeneous catalyst caused by K2CO3.

We demonstrate a scalable continuous feed method for the synthesis of polymer Janus nanoparticles with different composition and with different aspect ratios between lobes, including with one hard cross-linked polystyrene lobe and one soft film-forming poly(methyl methacrylate-co-butyl acrylate) (P(MMA-co-BA)) lobe, through reversible addition-fragmentation chain transfer (RAFT)-mediated emulsion polymerization. Snowman shaped particles of size around 40 nm are synthesized through a continuous monomer feeding method, which enables kilogram-scale synthesis of diverse polymer Janus nanoparticles, with a solids content greater than 30%. The Janus nanoparticles with the soft P(MMA-co-BA) lobes spontaneously self-assemble around solid particles in an aqueous phase, forming a thin (5 -100 nm) polymer film that completely encapsulates the solid particles. The process is achieved at room temperature and under mild conditions. The film-forming Janus nanoparticles show excellent encapsulation ability for a variety of solid particles, such as organic and inorganic pigments, carbon nanotubes and calcite, without requiring polymerization to be conducted in the presence of the solid particles. When the Janus nanoparticles were used to encapsulate calcite particles in low sheen paints, the encapsulation provided superior stain resistance to the formed paint film.

Under mild conditions of room temperature and pressure, and using either pure oxygen or air, aldehydes are converted using a heterogeneous Fe–N/C catalyst to produce the corresponding organic peroxy acid and acylperoxy radicals, which forms the epoxide from cyclohexene with high yield (91% for isobutyraldehyde in O2). Real-time monitoring of the rate of oxygen consumption and the electrochemical potential of the Fe–N/C catalyst has been used to study the formation of the peroxy acid and subsequent catalytic epoxidation of cyclohexene. Using isobutyraldehyde, it is shown that the aldehyde and the iron-based carbon catalyst (Fe–N/C) are involved in the rate determining step. Addition of a radical scavenger increases the induction time showing that radicals are initiated by the reaction between the aldehyde and the catalyst. Furthermore, UV-vis spectroscopy with 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid) (ABTS) proved the in situ formation of peroxy acid. In the presence of cyclohexene, the peroxy acid leads to the corresponding epoxide with high yield. Monitoring the open circuit potential (OCP) and oxygen flow concurrently follows the production of the peroxy acid. The epoxidation reaction can take place only when the increase in open circuit potential is greater than 0.14 V, suggesting an in situ direct link between the relative oxidative strength of the peroxy acid and the likelihood of epoxidation.

The use of perovskite materials for thermochemical energy storage and oxygen separation has been gaining momentum in recent years due to their ability to topotactically exchange large volumes of oxygen, and their chemical and structural flexibility. B-site substituted SrCoO3-δ derivatives have previously been investigated as promising materials for intermediate temperature solid oxide fuel cell cathodes due to the stabilization of a 3 C perovskite structure with high electronic and ionic conductivity that allows large oxygen storage capabilities. Here, antimony-substituted strontium cobalt oxides are investigated and identified as new candidate materials for thermochemical oxygen separation applications. In this work we shed light on the exceptional redox kinetics and cyclability of antimony-substituted variants undergoing oxygen exchange at intermediate temperatures (500 to 800 °C). Through the use of density functional theory and isothermal gas atmosphere switching, we demonstrate how the inductive effect of the more electronegative antimony dopants in the Co position, facilitates the kinetics of metal oxide oxidation, whilst hindering reduction reactions. SrCo0.95Sb0.05O3−δ was identified to isothermally evolve 3.76 cm3 g−1 of oxygen at 500 °C and calculated to produce up to 10.44 cm3 g−1 under temperature-swing reaction configurations aligning with previously reported materials.

Bubble size distribution (BSD) is a factor that is well known for influencing the performance of many industrial processes, such as froth flotation. The most commonly used method for measuring bubble size consists of processing photographs of the bubbles. However, the source code of the algorithms for performing the image processing has been seldom published. This article addresses the above by presenting a comprehensive open-source software for processing images of bubbles, allowing researchers to quantify BSD. This software - Bubble Analyser - includes a standard image processing algorithm that was tested against manually segmented images, showing errors under 5% in the calculation of the Sauter mean diameter, the most common descriptor of BSD. Additionally, Bubble Analyser has been designed to easily incorporate new segmentation algorithms developed by other researchers, in order to expand the software capabilities, allow for algorithm comparisons, and foster collaboration in research.

We present observations of >10-100 keV/nucleon suprathermal (ST) H, He, O, and Fe ions associated with crossings of the heliospheric current sheet (HCS) at radial distances, 4 Figures, 2 Tables

Funder: Shell Global Solutions International B.V., Direct growth of resorcinol−formaldehyde carbon aerogels (CAGs) on carbon paper electrodes was achieved using a new approach. Materials with variations in density, mesoporosity and microporosity were prepared. Microstructural properties of the resultant thin electrodes are shown to directly influence performance in zero‐gap redox flow battery (RFB). BET analysis shows a total surface area between 643 to 931 m2 g−1. Deposition of only ≈15 wt.% CAG on the carbon electrode leads to a 320‐fold increase in electrochemical surface area. Analysis of the results saw a strong positive correlation of RFB performance with surface area. The best performing electrodes had a good balance between microporous and external surface area, and on the macroscopic scale had sufficiently large pores to allow efficient electrolyte permeation. The poorest performing electrodes which had the highest surface area, also had poor macroscopic porosity leading to large mass transport and solution resistance losses. The best performing electrodes were tested in a zero‐gap setup using polarization curves, showing a 25 % increase in power density at 100 mA cm−2 and a peak power density of 706 mW cm−2 at 1 V using thin electrodes.