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We investigated the effect of ion pairs on the structure of complex coacervate core hydrogels (C3Gs) using small-angle X-ray/neutron scattering. The ratio between ammonium and guanidinium groups modulates both structure and salt-responsiveness of C3Gs as stimuli-responsive materials.

Small angle scattering affords an approach to evaluate the structure of dilute populations of macromolecules in solution where the measured scattering intensities relate to the distribution of scattering-pair distances within each macromolecule. When small angle neutron scattering (SANS) with contrast variation is employed, additional structural information can be obtained regarding the internal organization of biomacromolecule complexes and assemblies. The technique allows for the components of assemblies to be selectively 'matched in' and 'matched out' of the scattering profiles due to the different ways the isotopes of hydrogen-protium

Acta crystallographica / Section D 78(11), 1315 - 1336 (2022). doi:10.1107/S2059798322009184, Through an expansive international effort that involved data collection on 12 small-angle X-ray scattering (SAXS) and four small-angle neutron scattering (SANS) instruments, 171 SAXS and 76 SANS measurements for five proteins (ribonuclease A, lysozyme, xylanase, urate oxidase and xylose isomerase) were acquired. From these data, the solvent-subtracted protein scattering profiles were shown to be reproducible, with the caveat that an additive constant adjustment was required to account for small errors in solvent subtraction. Further, the major features of the obtained consensus SAXS data over the q measurement range 0$^{–1}$ Å$^{–1}$ are consistent with theoretical prediction. The inherently lower statistical precision for SANS limited the reliably measured q-range to 2.2 Å$^{–1}$ showed good mutual agreement, affirming that this region has interpretable features for structural modelling. SAS measurements with inline size-exclusion chromatography (SEC) proved to be generally superior for eliminating sample heterogeneity, but with unavoidable sample dilution during column elution, while batch SAS data collected at higher concentrations and for longer times provided superior statistical precision. Careful merging of data measured using inline SEC and batch modes, or low- and high-concentration data from batch measurements, was successful in eliminating small amounts of aggregate or interparticle interference from the scattering while providing improved statistical precision overall for the benchmarking data set., Published by Wiley, Bognor Regis

Synthesizing mesoporous alloys composed of metals with divergent reactivities and standard redox potentials (E0) is challenging because the kinetics of metal deposition is totally different. Herein, we report the first method to generate mesoporous RhNi alloy films via electrochemical co-deposition using self-assembled micelle templates. The concentration of Rh precursor (Rh3+) is crucial to control reaction kinetics and morphology because Rh deposition is the trigger of Ni co-deposition. The ratio of Rh3+ : Ni2+ (in the precursor) can be altered to generate different alloy compositions, and the impact of pH and deposition potentials is also investigated. We examine the mesoporous RhNi films as electrocatalytic electrodes for the hydrogen evolution reaction (HER). Ni-doping serves to enhance the HER performance of the mesoporous films, and the 1 : 1 alloy (mesoporous Rh49Ni51 film) shows the best performance with the overpotential of 59 mV @ 10 mA cm−2 and Tafel slope of 67 mV dec−1. The insight gained here will enable researchers to experiment with different noble-transition metal alloys to generate better porous electrodes for electrocatalysis.

Two-dimensional (2D) sandwich-structured phosphorus- and nitrogen-doped mesoporous carbon nanosheets have been synthesized by using graphene oxide (GO) as the substrate, triblock copolymer F127 mic...

Decagram scale syntheses of deuterated mineral oil (d-MO) and poly(1-decene) (d-PD) were achieved by direct catalytic hydrothermal H/D exchange reaction in D2O. Nuclear magnetic resonance (NMR), mass density and small angle neutron scattering (SANS) analyses collectively revealed deuteration ratios of 54 ± 12% and 88 ± 4% for d-MO and d-PD, respectively. Further SANS analyses of polyethylene (PE) dissolved in d-MO revealed that the oil behaved as a theta solvent at temperatures of 100 and 120 °C, based on assessments of the radii of gyration and mass-fractal dimensions in the PE coils. These results suggest that PE chains in d-MO likely adopt the same coiled molecular conformations as those reported for PE in the molten state. This approach of deuterating the oil solvent, in lieu of the polymer analyte, may have far reaching applications for the SANS assessments of oil additives in polymer materials. Additionally, such deuterated oils are expected to exhibit improved stability and oxidative resistance, which will benefit many applications given the ubiquitous use of mineral oil in industry.

The conformation of the polycation in the prototypical polymeric ionic liquid (PIL) poly(3-methyl-1-aminopropylimidazolylacrylamide) bis(trifluoromethylsulfonyl)imide (poly(3MAPIm)TFSI) was probed using small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS) at 25 °C and 80 °C. Poly(3MAPIm)TFSI contains microvoids which lead to intense low

This structural study exploits the possibility to use modular protein deuteration to facilitate the study of ubiquitin signalling, transfer, and modification. A protein conjugation reaction is used to combine protonated E2 enzyme with deuterated ubiquitin for small angle X-ray and neutron scattering with neutron contrast variation. The combined biomolecules stay as a monodisperse system during data collection in both protonated and deuterated buffers indicating long stability of the E2-Ub conjugate. With multiphase ab initio shape restoration and rigid body modelling, we reconstructed the shape of a E2-Ub-conjugated complex of UBE2D1 linked to ubiquitin via an isopeptide bond. Solution X-ray and neutron scattering data for this E2-Ub conjugate in the absence of E3 jointly indicate an ensemble of open and backbent states, with a preference for the latter in solution. The approach of combining protonated and labelled proteins can be used for solution studies to assess localization and movement of ubiquitin and could be widely applied to modular Ub systems in general. Funding Agencies|Swedish Foundation for Strategic Research within the national graduate school SwedNess [GSn15-0008]; Swedish Research Council (VR) [2018-04392]; Linkoping University

Small-angle scattering (SAS) is a technique commonly used in the soft matter sciences to characterize the structure of molecules self-assembling in solution. As such, it is suitable to study preparations of homogeneous liposomes to extract simple structural parameters such as radius and lipid bilayer thickness in solution. Here, we describe the preparation of liposomes for small-angle neutron scattering via extrusion and present the simplest way the resulting data can be modeled.

Small-angle scattering (SAS) is a technique commonly used in the soft matter sciences to characterize the structure of molecules self-assembling in solution. As such, it is suitable to study preparations of homogeneous liposomes to extract simple structural parameters such as radius and lipid bilayer thickness in solution. Here, we describe the preparation of liposomes for small-angle neutron scattering via extrusion and present the simplest way the resulting data can be modeled.

Nanozymes (nanoparticles with enzyme-like properties) have attracted considerable attention in recent years owing to their intrinsic enzyme-like properties and broad application in the fields of ELISA based immunoassay and biosensing. Herein, we systematically investigate the influence of crystal phases (γ-Fe2O3 and α-Fe2O3) of mesoporous iron oxide (IO) on their peroxidase mimetic activity. In addition, we have also demonstrated the applicability of these mesoporous IOs as nanozymes for detecting the glucose biomarker with a limit of detection (LOD) of 0.9 μM. Mesoporous γ-Fe2O3 shows high nanozyme activities (and magnetism) toward the catalytic oxidation of chromogenic substances, such as 3,3',5,5'-tetramethylbenzidine (TMB) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)-ABTS, as well as for the colourimetric detection of glucose, compared to that of α-Fe2O3. We believe that this in-depth study of crystal structure based nanozyme activity will guide designing highly effective nanozymes based on iron oxide nanostructures for chemical sensing, biosensing and environmental remediation.

AlphaB crystallin (αB-crystallin) is a key protein for maintaining the long-term transparency of the eye lens. In the eye lens, αB-crystallin is a “dynamical” oligomer regulated by subunit exchange between the oligomers. To elucidate the unsettled mechanism of subunit exchange in αB-crystallin oligomers, the study was carried out at two different protein concentrations, 28.5 mg/mL (dense sample) and 0.45 mg/mL (dilute sample), through inverse contrast matching small-angle neutron scattering. Interestingly, the exchange rate of the dense sample was the same as that of the dilute sample. From analytical ultracentrifuge measurements, the coexistence of small molecular weight components and oligomers was detected, regardless of the protein concentration. The model proposed that subunit exchange could proceed through the assistance of monomers and other small oligomers; the key mechanism is attaching/detaching monomers and other small oligomers to/from oligomers. Moreover, this model successfully reproduced the experimental results for both dense and dilute solutions. It is concluded that the monomer and other small oligomers attaching/detaching mainly regulates the subunit exchange in αB-crystallin oligomer.

Contains fulltext : 220423.pdf (Publisher’s version ) (Closed access) CNOT1 is a member of the CCR4-NOT complex, which is a master regulator, orchestrating gene expression, RNA deadenylation, and protein ubiquitination. We report on 39 individuals with heterozygous de novo CNOT1 variants, including missense, splice site, and nonsense variants, who present with a clinical spectrum of intellectual disability, motor delay, speech delay, seizures, hypotonia, and behavioral problems. To link CNOT1 dysfunction to the neurodevelopmental phenotype observed, we generated variant-specific Drosophila models, which showed learning and memory defects upon CNOT1 knockdown. Introduction of human wild-type CNOT1 was able to rescue this phenotype, whereas mutants could not or only partially, supporting our hypothesis that CNOT1 impairment results in neurodevelopmental delay. Furthermore, the genetic interaction with autism-spectrum genes, such as ASH1L, DYRK1A, MED13, and SHANK3, was impaired in our Drosophila models. Molecular characterization of CNOT1 variants revealed normal CNOT1 expression levels, with both mutant and wild-type alleles expressed at similar levels. Analysis of protein-protein interactions with other members indicated that the CCR4-NOT complex remained intact. An integrated omics approach of patient-derived genomics and transcriptomics data suggested only minimal effects on endonucleolytic nonsense-mediated mRNA decay components, suggesting that de novo CNOT1 variants are likely haploinsufficient hypomorph or neomorph, rather than dominant negative. In summary, we provide strong evidence that de novo CNOT1 variants cause neurodevelopmental delay with a wide range of additional co-morbidities. Whereas the underlying pathophysiological mechanism warrants further analysis, our data demonstrate an essential and central role of the CCR4-NOT complex in human brain development.

The effect of Mo on the clustering and interphase precipitation occurring during phase transformation has been investigated in a strip-cast low-carbon steel containing Nb. In this work, isothermal coiling treatments were performed at 700 °C for various times to form interphase precipitates. Transmission electron microscopy (TEM), small-angle neutron scattering (SANS) and atom probe tomography (APT) results show that the addition of Mo increases the number density and volume fraction of clusters and interphase precipitates but has a negligible effect on their size, and overall provides for greater strengthening in the Mo-containing alloy. APT analysis shows that the interphase precipitates are composed of Nb, C and N in both alloys. The segregation of Mo is also observed in the interphase precipitates in the Mo-containing alloy, which is believed to relieve the lattice misfit between the precipitate and the matrix. It is proposed that the reduced lattice misfit allows for precipitate nucleation to occur more easily in the Mo-containing alloy Refereed/Peer-reviewed

Two-dimensional (2D) metals are an emerging class of nanostructures that have attracted enormous research interest due to their unusual electronic and thermal transport properties. Adding mesopores in the plane of ultrathin 2D metals is the next big step in manipulating these structures because increasing their surface area improves the utilization of the material and the availability of active sites. Here, we report a novel synthetic strategy to prepare an unprecedented type of 2D mesoporous metallic iridium (Ir) nanosheet. Mesoporous Ir nanosheets can be synthesized with close-packed assemblies of diblock copolymer (poly-(ethylene oxide)- b-polystyrene, PEO- b-PS) micelles aligned in the 2D plane of the nanosheets. This novel synthetic route opens a new dimension of control in the synthesis of 2D metals, enabling new kinds of mesoporous architectures with abundant catalytically active sites. Because of their unique structural features, the mesoporous metallic Ir nanosheets exhibit a high electrocatalytic activity toward the oxygen evolution reaction (OER) in acidic solution as compared to commercially available catalysts.

An atom probe tomography data analysis procedure for identification of particles in a Ti-Mo steel is presented. This procedure has been used to characterise both carbide precipitates (larger particles) and solute clusters (smaller particles), as reported in an accompanying Mater. Sci. Eng. A paper [1]. Particles were identified using the maximum separation method (cluster-finding algorithm) after resolving peak overlaps at several locations in the mass spectrum. The cluster-finding algorithm was applied to the data in a two-stage process to properly identify particles having a bimodal size distribution. Furthermore, possible misidentification of matrix atoms (mainly Fe) due to the local magnification effect (from the difference in field evaporation potential between the matrix and precipitates) has been resolved using an atomic density approach, comparing that measured experimentally using APT to the theoretical density of both the matrix and particles.

QUOKKA is a 40 m pinhole small-angle neutron scattering instrument in routine user operation at the OPAL research reactor at the Australian Nuclear Science and Technology Organisation. Operating with a neutron velocity selector enabling variable wavelength, QUOKKA has an adjustable collimation system providing source–sample distances of up to 20 m. Following the large-area sample position, a two-dimensional 1 m2 position-sensitive detector measures neutrons scattered from the sample over a secondary flight path of up to 20 m. Also offering incident beam polarization and analysis capability as well as lens focusing optics, QUOKKA has been designed as a general purpose SANS instrument to conduct research across a broad range of scientific disciplines, from structural biology to magnetism. As it has recently generated its first 100 publications through serving the needs of the domestic and international user communities, it is timely to detail a description of its as-built design, performance and operation as well as its scientific highlights. Scientific examples presented here reflect the Australian context, as do the industrial applications, many combined with innovative and unique sample environments.

The isothermal evolution of nanometre-sized precipitates formed in a Ti-Mo microalloyed steel through interphase precipitation has been investigated using atom probe tomography and small-angle neutron scattering. The coiling time and applied strain have been varied to observe the precipitate evolution at a constant coiling temperature of 650 °C, where various evolution parameters such as particle radius, number density, volume fraction and chemical composition have been evaluated and compared. The possibility of early stage solute clustering and its effect on precipitate formation have also been investigated. Clustering of Ti, Mo and C atoms as Ti-C and Mo-C has been observed at the shortest coiling time of 5 min. These clusters are assumed to be precursors to the carbide precipitates observed in the system, which exhibit a metastable composition, containing a carbon fraction (C/Ti+Mo ratio) in the range of 0.2–1. In particles having a Guinier radius > 3 nm, however, the average chemical composition approached the stable MC carbide stoichiometry with Ti/Mo ratio ~2.5 and C/(Ti+Mo) ratio ~0.55. This study reveals that the precipitate coarsening kinetics are very slow, with average particle diameter 10 h) in both the undeformed and deformed conditions. This is believed to be due to the reduction in equilibrium Ti content in the matrix as a result of partial replacement of Ti by Mo (Ti/Mo ratio > 2) in the precipitate lattice, in the presence of excess C in the system.

A model membrane system has been developed, which mimics the outer membrane of Gram negative bacteria. The structure is based on a tethered monolayer which has been fused with vesicles containing lipopolysaccharide molecules. The effect of the composition of the monolayer and the lipids in the outer layer on the structural and electrical properties of the membrane has been investigated. By using electrochemical impedance spectroscopy as well as neutron scattering techniques, it could be shown that a relatively high tethering density and a small amount of diluting lipids in the outer membrane leaflet leads to the formation of a stable solid supported membrane. The influence of divalent ions on the membrane stability has been probed as well as the interaction of the bilayer with the antibiotic colistin. A number of different architectures were developed, suited to both the study of bacterial membrane proteins and the screening of antimicrobial activity of potential drug candidates.

Mesoporous noble metals are an emerging class of cutting-edge nanostructured catalysts due to their abundant exposed active sites and highly accessible surfaces. Although various noble metal (e.g. Pt, Pd and Au) structures have been synthesized by hard- and soft-templating methods, mesoporous rhodium (Rh) nanoparticles have never been generated via chemical reduction, in part due to the relatively high surface energy of rhodium (Rh) metal. Here we describe a simple, scalable route to generate mesoporous Rh by chemical reduction on polymeric micelle templates [poly(ethylene oxide)-b-poly(methyl methacrylate) (PEO-b-PMMA)]. The mesoporous Rh nanoparticles exhibited a ∼2.6 times enhancement for the electrocatalytic oxidation of methanol compared to commercially available Rh catalyst. Surprisingly, the high surface area mesoporous structure of the Rh catalyst was thermally stable up to 400 °C. The combination of high surface area and thermal stability also enables superior catalytic activity for the remediation of nitric oxide (NO) in lean-burn exhaust containing high concentrations of O2., Mesoporous noble metal nanostructures offer great promise in catalytic applications. Here, Yamauchi and co-workers synthesize mesoporous rhodium nanoparticles using polymeric micelle templates, and report appreciable activities for methanol oxidation and NO remediation.

A small arc of islands in the Tropical Western Atlantic, the Turks, and Caicos Islands faces significant challenges in developing a tourism economy while protecting fragile island ecosystems, particularly fringing and barrier coral reefs. The islands are particularly low lying, with a tropical dry climate; historically this climate was exploited for solar salt production. The Turks and Caicos today rely exclusively on tourism for their economy. Recent large hurricanes and the threat of sea level rise have challenged the existing development and infrastructure of the islands.

Unexplained elevated intracranial pressure occasionally develops in individuals with Multiple Sclerosis (MS). Visual symptoms and signs are common to both conditions. An awareness of this association is particularly relevant due to the increased incidence of headache in MS and the frequent overlap of symptoms and signs in both conditions.

The effect of a simulated coiling treatment on a strip cast Nb-containing steel has been investigated. A lath ferritic supersaturated microstructure was observed in the as-cast condition with no coiling. The microstructure remained lath like during coiling at high temperature (850 °C) and the formation of chemically complex Nb-rich precipitates containing C, N, Si and S was observed. Coiling at an intermediate temperature (700 °C) caused the formation of polygonal ferrite with a dendritic morphology due to chemical micro-segregation. The polygonal ferrite contained Nb(C,N) precipitates. The microstructure remained lath like at the lowest coiling temperature (600 °C). In the latter case the precipitation of Nb-rich clusters was observed, and atom probe tomography revealed them to be ∼85% Fe. Small angle neutron scattering and transmission electron microscopy were used to quantify precipitation kinetics during coiling and the mechanical properties were evaluated with a shear punch apparatus. A yield strength model was developed to describe the observed mechanical behaviour, and this showed that the two largest contributors to strength were the bainitic microstructure and the Nb-rich precipitates. Strategies to further strengthen these materials are suggested. Refereed/Peer-reviewed

The formation of amyloid deposits is a common feature of a broad range of diseases, including atherosclerosis, Alzheimer's disease, and Parkinson's disease. The basis and role of amyloid deposition in the pathogenesis of these diseases is still being defined, however an interesting feature of amyloidogenic proteins is that the majority of the pathologically associated proteins are involved in lipid homeostasis, be it in lipid transport, incorporation into membranes, or the regulation of lipid pathways. Thus, amyloid-forming proteins commonly bind lipids, and lipids are generally involved in the proper folding of these proteins. However, understanding of the basis for these lipid-related aspects of amyloidogenesis is lacking. Thus, we have used the apolipoprotein C-II amyloid model system in conjunction with x-ray and neutron scattering analyses to address this problem. Apolipoprotein C-II is a well-studied model system of systemic amyloid fibril formation, with a clear and well-defined pathway for fibril formation, where the effects of lipid interaction are characterized, particularly for the lipid mimetic dodecylphosphocholine. We show that the micellar state of an inhibitory lipid can have a very significant effect on protein conformation, with micelles stabilizing a particular α-helical structure, whereas submicellar lipids stabilize a very different dimeric, α-helical structure. These results indicate that lipids may have an important role in the development and progression of amyloid-related diseases.

Advances in nanoarchitectonics enable a wide variety of nanostructured electrodes with tunable shapes and surface for constructing sensitive biosensors. Herein we demonstrate the fabrication of a mesoporous gold (Au) biosensor for the specific and sensitive detection of miRNA in a relatively simple and portable manner. The electrocatalytic activity of the mesoporous Au electrode (MPGE) towards the redox reaction of Fe(CN)6]3-/4- expansively examined. Leveraging the electrocatalytic activity and signal enhancement capacity of the MPGE, an ultrasensitive and specific electrochemical sensor was developed for the detection of microRNA (miRNA). The target miRNA from spiked samples is selectively isolated and purified using magnetic bead-capture probe followed by the direct adsorption on the MPGE through direct affinity interaction between miRNA and mesoporous Au surface. The MPGE-bound miRNA is then quantified by differential pulse voltammetry (DPV) using [Fe(CN)6]4-/3- redox system (Faradaic current decrease with reference to the bare MPGE). This method evades the cumbersome PCR (polymerase chain reaction) and enzymatic amplification steps. This is a single-step assay building which can detect a wide dynamic linear range (100 aM to 1 nM) of miRNA with an ultra-low limit detection of 100 aM and present high translational potentiality for the development of high-performance detection tools for clinics.

The electrochemical synthesis of mesoporous ruthenium (Ru) films using sacrificial self-assembled block polymer micelles templates, and its electrochemical surface oxidation to RuOx is described. Unlike standard methods such as thermal oxidation, the electrochemical oxidation method described here retains the mesoporous structure. Ru oxide materials serve as high-performance supercapacitor electrodes due to their excellent pseudocapacitive behavior. The mesoporous architectured film shows superior specific capacitance (467 F g-1 Ru ) versus a nonporous Ru/RuOx electrode (28 F g-1 Ru ) that is prepared via the same method but omitting the pore-directing polymer. Ultrahigh surface area materials will play an essential role in increasing the capacitance of this class of energy storage devices because the pseudocapacitive redox reaction occurs on the surface of electrodes.

Since the mid-1980s, participants in community supported agriculture (CSA) have promoted, proliferated, and adapted the CSA model, resulting in CSAs gaining popularity as a trusted "brand." They have developed and expanded CSA by pursuing common branding strategies, such as building name recognition, differentiating the brand from other farm and food producers, and developing CSA narratives and mythologies with positive associations that attract advocates. However, CSA has not been branded via a typical centralized, hierarchical process, but rather through the independent, informally organized collective efforts of its farmers and members. With no standardized licensing or certification process (unlike "organic"), CSAs remain liberated from a strict set of allowed practices, yet debates still occur about what constitutes a "real" CSA. Despite the fact that many idealistic promotional claims of CSA have been validated, one glaring weakness is that many CSA farmers still struggle to achieve financial security. The positive brand mythology surrounding CSA has made it difficult for participants to acknowledge and confront this shortcoming. Drawing on qualitative field research and review of archival CSA materials, this paper examines the identity making and branding of CSA. I constructively critique some of the most fundamental aspects of CSA: its constructed image and its actual practice. Through this lens, I ask how the independent, open-source branding has helped or hindered CSA proponents in achieving goals. By focusing on these aspects my hope is that a variety of advocates, academics, farmers, CSA members, and others, can collaborate on developing a positive next era for CSA and its offshoots both within and beyond agriculture and food—projects aimed at strengthening consumer/producer alliances, cooperative practices, and ethically based community economies.

Localized agriculture is theorized to provide socio-environmental benefits to the community while ensuring a livelihood for local farmers. Much of the food systems literature refers to such an arrangement as civic agriculture, which is characterized as promoting community development by strengthening social ties among the various nodes of the localized food system. However, there is little literature that identifies the attributes of community and the specific mechanisms through which community qualities are produced, modeled, or replicated. This study's goal is to identify the meaning of community as used in the phrase "community supported agriculture" (CSA) by asking members and operators of local CSAs how they define community within the context of their membership. On-site interviews were conducted at the produce pick-up locations of four CSA farms in central Pennsylvania, resulting in a convenience sample of 97 CSA members and four operators. The survey instrument utilized open and closed-ended questions to collect information on farmer and member perceptions of their CSA community, motivations to join, and satisfaction with their experiences. The results suggest respondents are highly satisfied with products and services provided through their CSA. However, there are statistically significant differences in satisfaction scores across the four sampled farms. These differences support findings drawn from the open-ended questions indicating these CSA farms varied in member-defined attributes of a CSA community. Farm management practices, level of personal interactions, and other factors appear to have significant effects on CSA members' perception of community.

The formation of bilayer-based lyotropic liquid crystals and vesicle dispersions by phospholipids in a range of protic ionic liquids has been investigated by polarizing optical microscopy using isothermal penetration scans, differential scanning calorimetry, and small angle X-ray and neutron scattering. The stability and structure of both lamellar phases and vesicle dispersions is found to depend primarily on the underlying amphiphilic nanostructure of the ionic liquid itself. This finding has significant implica-tions for the use of ionic liquids in soft and biological materials and for biopreservation, and demon-strates how vesicle structure and properties can be controlled through selection of cation and anion. For a given ionic liquid, systematic trends in bilayer thickness, chain-melting temperature and enthalpy in-crease with phospholipid acyl chain length, paralleling behaviour in aqueous systems. Australian Research Council, ANSTO, AINSE

Mesoporous metals that combine catalytic activity and high surface area can provide more opportunities for electrochemical applications. Various synthetic methods, including hard and soft templating, have been developed to prepare mesoporous/nanoporous metals. Micelle assembly, typically involved in soft-templates, is flexible and convenient for such purposes. It is, however, difficult to control, and the ordering is significantly destroyed during the metal deposition process, which is detrimental when it comes to designing precisely mesostructured materials. In the present work, mesoporous Pd films were uniformly electrodeposited using a nonionic surfactant, triblock copolymer poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), as a pore-directing agent. The interaction between micelles and metal precursors greatly influences the metal growth and determines the final structure. The water-coordinated species interact with the ethylene oxide moiety of the micelles to effectively drive the Pd(II) species toward the working electrode surface. From small-angle neutron scattering data, it is found that spherical P123 micelles, with an average diameter of ∼14 nm, are formed in the electrolyte, and the addition of Pd ions does not significantly modify their structure, which is the essence of the micelle assembly approach. The uniformly sized mesopores are formed over the entire mesoporous Pd film and have an average pore diameter of 10.9 nm. Cross-sectional observation of the film also shows mesopores spanning continuously from the bottom to the top of the film. The crystallinity, crystal phase, and electronic coordination state of the Pd film are also confirmed. Through this study, it is found that the optimized surfactant concentration and applied deposition potential are the key factors to govern the formation of homogeneous and well-distributed pores over the entire film. Interestingly, the as-prepared mesoporous Pd films exhibit superior electrocatalytic activity toward the ethanol oxidation reaction by fully utilizing the accessible active surface area. Our approach combines electrochemistry with colloidal and coordination chemistry and is widely applicable to other promising metals and alloy electrocatalysts.