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Unravelling cationic cellulose nanofibril hydrogel structure : NMR spectroscopy and small angle neutron scattering analyses

Stiff, elastic, viscous shear thinning aqueous gels are formed upon dispersion of low weight percent concentrations of cationically modified cellulose nanofibrils (CCNF) in water. CCNF hydrogels produced from cellulose modified with glycidyltrimethylammonium chloride, with degree of substitution (DS) in the range 10.6(3)-23.0(9)%, were characterised using NMR spectroscopy, rheology and small angle

Decyltrimethylammonium Bromide Micelles in Acidic Solutions : Counterion Binding, Water Structuring, and Micelle Shape

Wide-angle neutron scattering experiments combined with empirical potential structural refinement modeling have been used to study the detailed structure of decyltrimethylammonium bromide micelles in the presence of acid solutions of HCl or HBr. These experiments demonstrate considerable variation in micelle structure and water structuring between micelles in the two acid solutions and in comparis

Thermal stability, storage and release of proteins with tailored fit in silica

Biological substances based on proteins, including vaccines, antibodies, and enzymes, typically degrade at room temperature over time due to denaturation, as proteins unfold with loss of secondary and tertiary structure. Their storage and distribution therefore relies on a “cold chain” of continuous refrigeration; this is costly and not always effective, as any break in the chain leads to rapid lo

Microwave-assisted deep eutectic-solvothermal preparation of iron oxide nanoparticles for photoelectrochemical solar water splitting

Here, we present a new microwave-solvothermal method for the preparation of iron oxide nanostructures using deep eutectic solvents as a more sustainable reaction medium. By varying the synthesis temperature and solvent water fraction, the methodology offers control over iron oxide phase, size, and morphology, using efficient, rapid (10 minute) microwave heating. Synthesis with pure DES gives small

The Effect of Water upon Deep Eutectic Solvent Nanostructure : An Unusual Transition from Ionic Mixture to Aqueous Solution

The nanostructure of a series of choline chloride/urea/water deep eutectic solvent mixtures was characterized across a wide hydration range by neutron total scattering and empirical potential structure refinement (EPSR). As the structure is significantly altered, even at low hydration levels, reporting the DES water content is important. However, the DES nanostructure is retained to a remarkably h

Sulfur-Doped Cubic Mesostructured Titania Films for Use as a Solar Photocatalyst

Sulfur-doped titania thin films with cubic mesostructures were prepared by dip coating via the evaporation induced self-assembly route. The effect of sulfur doping on structure, morphology, porosity, optical properties, and photocatalytic activity of the mesoporous films was studied. Compared to undoped titania films, the S-doped films showed better long-range ordering, bigger pore size, higher po

Coarse-grained empirical potential structure refinement : Application to a reverse aqueous micelle

Conventional atomistic computer simulations, involving perhaps up to 106 atoms, can achieve length-scales on the order of a few 10s of nm. Yet many heterogeneous systems, such as colloids, nano-structured materials, or biological systems, can involve correlations over distances up 100s of nm, perhaps even 1 μm in some instances. For such systems it is necessary to invoke coarse-graining, where sin

Free-Standing Phytantriol Q224 Cubic-Phase Films : Resistivity Monitoring and Switching

Phytantriol Q224 cubic phase, as a bicontinuous meso-structured material stable in contact with aqueous electrolyte, has found applications in drug delivery and cosmetics and is employed here as a free-standing film separating two aqueous compartments in order to study i) ion conductivity (at low potential bias within ±0.8 V), ii) conductivity switching effects (at high potential bias beyond ±0.8

Deep eutectic-solvothermal synthesis of nanostructured ceria

Ceria is a technologically important material with applications in catalysis, emissions control and solid-oxide fuel cells. Nanostructured ceria becomes profoundly more active due to its enhanced surface area to volume ratio, reactive surface oxygen vacancy concentration and superior oxygen storage capacity. Here we report the synthesis of nanostructured ceria using the green Deep Eutectic Solvent

Atomistic modelling of scattering data in the ollaborative Computational Project for Small Angle Scattering (CCP-SAS)

The capabilities of current computer simulations provide a unique opportunity to model small-angle scattering (SAS) data at the atomistic level, and to include other structural constraints ranging from molecular and atomistic energetics to crystallography, electron microscopy and NMR. This extends the capabilities of solution scattering and provides deeper insights into the physics and chemistry o

Evidence of Lipid Exchange in Styrene Maleic Acid Lipid Particle (SMALP) Nanodisc Systems

Styrene-alt-maleic acid lipid particles (SMALPs) are self-assembled discoidal structures composed of a polymer belt and a segment of lipid bilayer, which are capable of encapsulating membrane proteins directly from the cell membrane. Here we present evidence of the exchange of lipids between such "nanodiscs" and lipid monolayers adsorbed at either solid-liquid or air-liquid interfaces. This behavi

Massive open online courses in chemistry : A comparative overview of platforms and features

Open-access, online educational platforms launched in the last decade are receiving growing attention from both academia and the general public. A special class of such courseware known as MOOCs (massive open online courses) allows enrollment of up to hundreds of thousands of students from all over the world. This report reviews and compares currently available chemistry MOOCs as well as other Web

Broad spectral photocurrent enhancement in Au-decorated CdSe nanowires

Metal-semiconductor hybrid nanostructures promise improved photoconductive performance due to plasmonic properties of the metal portions and intrinsic electric fields at the metal-semiconductor interface that possibly enhance charge separation. Here we report gold decorated CdSe nanowires as a novel functional material and investigate the influence of gold decoration on the lateral facets on the p

A new route to produce efficient surface-enhanced Raman spectroscopy substrates : Gold-decorated CdSe nanowires

Surface-enhanced Raman spectroscopy is a popular tool for the detection of extremely small quantities of target molecules. Au nanoparticles have been very successful in this respect due to local enhancement of the light intensity caused by their plasmon resonance. Furthermore, Au nanoparticles are biocompatible, and target substances can be easily attached to their surface. Here, we demonstrate th

Chemically induced self-assembly of spherical and anisotropic inorganic nanocrystals

The self-assembly of inorganic nanoparticles is a research area of great interest aiming at the fabrication of unique mesostructured materials with intrinsic properties. Although many assembly strategies have been reported over the years, chemically induced self-assembly remains one of the dominant approaches to achieve a high level of nanoparticle organization. In this feature article we will rev

Synthesis and characterization of azidoalkyl-functionalized gold nanoparticles as scaffolds for "click"-chemistry derivatization

We demonstrate how water-soluble gold nanoparticles prepared by the citrate reduction method can be functionalized with 11-azidoundecane-1-thiol in a single-step procedure, which combines phase transfer and ligand exchange. The advantages of our method include high reproducibility, low cost of gold nanoparticle production, and rapid and clean ligand exchange, with minimal intermediate steps and no

Assembly of shape-controlled nanocrystals by depletion attraction

Recently (Baranov et al., Nano Lett., 2010, 10, 743) we demonstrated that depletion attraction between semiconductor nanorods in solution can be employed for both their self-assembly and their separation from spherical nanoparticles. Here we show that depletion attraction can be used to fabricate binary superlattices of nanorods and 3D networks of octapod/tetrapod-shaped nanocrystals.

Phototransport in networks of tetrapod-shaped colloidal semiconductor nanocrystals

Tetrapod-shaped CdSe(core)/CdTe(arms) colloidal nanocrystals, capped with alkylphosphonic acids or pyridine, were reacted with various small molecules (acetic acid, hydrazine and chlorosilane) which induced their tip-to-tip assembly into soluble networks. These networks were subsequently processed into films by drop casting and their photoconductive properties were studied. We observed that films