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Ultrathin carbon film electrodes from vacuum-carbonised cellulose nanofibril composite

A novel way to produce ultrathin transparent carbon layers on tin-doped indium oxide (ITO) substrates is developed. The ITO surface is coated with cellulose nanofibrils (from sisal) via layer-by-layer electrostatic binding with poly(diallyldimethylammonium chloride) or PDDAC acting as the binder. The cellulose nanofibril-PDDAC composite film is then vacuum-carbonised at 5008C. The resulting carbon

Mesoporous titanium dioxide films using partially fluorinated surfactant templates in ethanol

Mesoporous titanium dioxide films have been produced via a self assembly pathway at the air-ethanol interface using partially fluorinated surfactants as structure directing agents. The high level of surface activity displayed by partially fluorinated compounds in alcohols has been used to generate an ordered film at the air-solution interface, as titanium oligomers condense into an ordered inorgan

Liquid crystal codendrimers with a statistical distribution of phenolic and mesogenic groups : Behavior as langmuir and langmuir - Blodgett films

The first series of carbosilane liquid crystal codendrimers with groups of different polarity has been synthesized. The chemical structure of the newly synthesized materials and the composition of the codendrimers were studied by NMR spectroscopy and MALDI-TOF MS. It was found that the codendrimers tend to form stable Langmuir films at the air-water surface. The influence of composition and genera

Structural evolution of surfactant - Silica film-forming solutions, investigated using small-angle neutron scattering

Time-resolved small-angle neutron scattering has been used to investigate the evolution of micelles in the subphase of surfactant-templated silica film-forming solutions. Two samples have been prepared using cetyltrimethylammonium bromide (CTABr), as the structure-directing agent, and different amounts of tetramethoxysilane (TMOS) (CTABr/TMOS molar ratio 0.093, 0.139). The solutions have been repr

Accessibility of dye molecules embedded in surfactant-silica hybrid materials in both powder and film forms

Two CTABr-silica mesophases have been prepared, one of them as a powder with hexagonal structure containing Congo Red, the other one as a film with cubic structure containing Disperse Red 1. In the former case the dye has been occluded via co-entrapping, whereas in the latter it has been covalently anchored to the silica matrix via a co-condensation route. In both systems, the dye molecules proved

Accessibility to gases of dye molecules in hybrid surfactant-silica mesophases

Two types of CTABr-silica mesophases have been prepared, one of them a powder with hexagonal structure containing Congo Red, another one a film with cubic structure containing Disperse Red 1. In the former case the dye has been occluded via co-entrapping, whereas in the latter it has been covalently anchored to the silica matrix via a co-condensation route. In both systems, the dye molecules prove

Underpotential surface reduction of mesoporous CeO 2 nanoparticle films

The formation of variable-thickness CeO 2 nanoparticle mesoporous films from a colloidal nanoparticle solution (approximately 1-3-nm-diameter CeO 2) is demonstrated using a layer-by-layer deposition process with small organic binder molecules such as cyclohexanehexacarboxylate and phytate. Film growth is characterised by scanning and transmission electron microscopies, X-ray scattering and quartz

Macroscopic, mesostructured cationic surfactant/neutral polymer films : Structure and cross-linking

Mesostructured films of alkyltrimethylammonium bromides or cetylpyridinium bromide and polyethylenimines that spontaneously self-assemble at the air/water interface have been examined using a range of surface sensitive techniques. These films are unusual in that they can be micrometers thick and are relatively robust. Here we show that the films can be cross-linked and thus removed from the liquid

Template-induced crystal growth

The process of "mineralisation" in biology leads to a diversity of inorganic structures based on silica or calcium carbonate. Some of these are composite and, at the same time, highly crystalline. In all cases a molecular or self assembled "template" species has been identified as the promoter for the crystallisation of the new structure. In biology these "templates" are the end step in the convey

Concentration-dependent formation mechanisms in mesophase silica-surfactant films

The development of surfactant-templated mesoporous films grown at the air/water interface was investigated using specular and off-specular X-ray reflectivity techniques. The samples were prepared in acidic conditions using cetyltrimethylammonium bromide (CTABr, 0.075 M) and different concentrations (0.27-0.88 M) of tetramethyloxysilane (TMOS). At CTABr/TMOS molar ratio between 0.277 and 0.093, the

The role of protein hydrophobicity in thionin-phospholipid interactions : A comparison of α1 and α2-purothionin adsorbed anionic phospholipid monolayers

The plant defence proteins α1- and α2-purothionin (Pth) are type 1 thionins from common wheat (Triticum aestivum). These highly homologous proteins possess characteristics common amongst antimicrobial peptides and proteins, that is, cationic charge, amphiphilicity and hydrophobicity. Both α1- and α2-Pth possess the same net charge, but differ in relative hydrophobicity as determined by C18 reverse

Formation of shear thinning gels from partially oxidised cellulose nanofibrils

Partially C(6) oxidised, dispersed cellulose nanofibres form shear thinning gels in the presence of moderate amounts of simple salts or surfactants providing a novel method to structure aqueous formulations, which may be of use in a substantial number of applications where it is desirable to enhance the viscosity of formulated materials using components from a renewable, sustainable source.

Preparation dependent stability of pure silica MCM-41

The degradation of pure silica MCM-41 materials prepared under various synthesis conditions has been investigated. Materials from preparations titrated with acid during synthesis not only show improved long range ordering of the pore system but also greater stability. This effect is greatest in unheated preparations.

Formation of mesophase surfactant-templated silica thin films from acidic solutions

The formation of mesophase silica-surfactant thin films at the air/solution interface has been studied in situ using off-specular X-ray reflectivity, Brewster angle microscopy and small angle scattering. Results for cetyltrimethylammonium bromide-templated films suggest that the formation mechanism is strongly dependent on the silica:surfactant ratio, and this is confirmed by studies on the subpha

Hydrothermal core-shell carbon nanoparticle films : Thinning the shell leads to dramatic pH response

Carbon nanoparticles with phenylsulfonate negative surface functionality (Emperor 2000, Cabot Corp.) are coated with positive chitosan followed by hydrothermal carbonization to give highly pH-responsive core-shell nanocarbon composite materials. With optimised core-shell ratio (resulting in an average shell thickness of ca. 4 nm, estimated from SANS data) modified electrodes exhibit highly pH-sens