Porous carbons from inverse vulcanised polymers

Elemental sulfur is an underutilised industrial by-product. It has been recently shown that it can be simply and scalably co-polymerised, by “inverse vulcanisation” with organic crosslinkers. The properties of porous carbons, which have extensive uses in science and industry, are influenced by the materials from which they are generated. Reported here are the first examples of porous carbons produced from high-sulfur inverse vulcanised polymers. The materials produced show micro-porosity, gas selectivity, and are doped with sulfur. The simplicity of the technique, and wide range of other potential inverse vulcanised feedstocks, gives scope for transferability and control of properties

VO2/TiO2 bilayer films for energy efficient windows with multifunctional properties

Vanadium dioxide/titanium dioxide bilayer films have been investigated as a thermochromic coating for application as intelligent window glazings for buildings. The nanostructured VO2 and TiO2 films were deposited on fluorine doped tin oxide coated glass substrates using electric field assisted aerosol assisted chemical vapour deposition (ElFi-AACVD) and sol-gel spin coating, respectively. Their thermochromic properties were investigated using scanning electron microscopy, X-ray diffraction, variable temperature UV/Vis/NIR and X-ray photoelectron spectroscopies. Compared to bare VO2 films, the VO2/TiO2 bilayer films exhibit an increase in visible light transmittance of up to 30%, an increase in integrated luminous transmisttance, with values up to 66%, and a higher transmittance modulation in the near infrared of up to 20% at the thermochromic transition temperature. The TiO2 top layer not only enhances visible light transmittance, but also serves to protect the VO2 bottom layer from oxidation. The bilayer films are shown to exhibit photo-induced super-hydrophilicity. These properties are affected by the morphology of the VO2 under-layer

Active removal of waste dye pollutants using Ta[sub]3N[sub]5/W[sub]18O[sub]49 nanocomposite fibres

A scalable solvothermal technique is reported for the synthesis of a photocatalytic composite material consisting of orthorhombic Ta3N5 nanoparticles and WOx≤3 nanowires. Through X-ray diffraction and X-ray photoelectron spectroscopy, the as-grown tungsten(VI) sub-oxide was identified as monoclinic W18O49. The composite material catalysed the degradation of Rhodamine B at over double the rate of the Ta3N5 nanoparticles alone under illumination by white light, and continued to exhibit superior catalytic properties following recycling of the catalysts. Moreover, strong molecular adsorption of the dye to the W18O49 component of the composite resulted in near-complete decolourisation of the solution prior to light exposure. The radical species involved within the photocatalytic mechanisms were also explored through use of scavenger reagents. Our research demonstrates the exciting potential of this novel photocatalyst for the degradation of organic contaminants, and to the authors’ knowledge the material has not been investigated previously. In addition, the simplicity of the synthesis process indicates that the material is a viable candidate for the scale-up and removal of dye pollutants on a wider scale

CD1a-positive infiltrating-dendritic cell density and 5-year survival from human breast cancer

© Churchill LivingstoneInfiltrating CD1a+ dendritic cells (DCs) have been associated with increased survival in a number of human cancers. This study investigated DC infiltration within breast cancers and the association with survival. Classical established prognostic factors, of tumour size, lymph node status, histological grade, lympho-vascular invasion, the KI-67 (MIB-1) fraction and the Nottingham Prognostic Index (NPI) were also compared. A total of 48 breast cancer patients were followed from the time of surgery and CD1a density analysis for 5 years or until death. Our data set validated previous studies, which show a relationship between survival and the NPI (P<0.001), tumour size (P<0.01) and lymph node status (P<0.05). Although more patients were alive at the 5-year time point in the group with higher CD1a DC density than the lower CD1a DC group, this failed to reach statistical significance at the P=0.05 level. Analysis at 10 years postsurgery is required to investigate the association further.B.J.Coventry and J. Morto

Combinatorial atmospheric pressure chemical vapour deposition (cAPCVD) of niobium doped anatase; effect of niobium on the conductivity and photocatalytic activity

Combinatorial atmospheric pressure chemical vapour deposition (cAPCVD) was used to synthesise anatase thin-films with gradating substitutionally doped niobium content on a single film. This is the first time such a combinatorial system has been formed by CVD or other means. The film was characterised via X-ray diffraction (XRD) mapping, Raman spectroscopy, atomic force microscopy (AFM), wavelength dispersive X-ray analysis (WDX) and X-ray photoelectron spectroscopy (XPS) analysis. Film thicknesses and band-gap energies were derived from Swanepoel thickness analysis and Tauc plots of transmittance spectra. Water droplet contact angle measurements displayed a UVC induced movement to super hydrophilic behaviour by a photo-induced superhydrophilicity (PSH) mechanism, irrespective of niobium levels. The film's conductivity and photocatalytic activity to different light sources were mapped using a four-point probe and novel flat-bed digital scanning technique. This allowed for the systematic investigation on the effect of niobium doping. It was found that film growth rate in addition to niobium concentration directly influenced photocatalytic activity and electrical conductivity. A direct relationship between conductivity of these Nb-doped anatase thin-films and photocatalytic activity to both UVA and indoor lighting was also observed. Films synthesized by the cAPCVD route analysed in conjunction with mapping analysis tools provide a shortcut to investigating the effect of metal dopant on the functional properties for a wide range of phase space on a single film, enabling rapid analysis

The relationship between photocatalytic activity and photochromic state of nanoparticulate silver surface loaded titanium dioxide thin-films

Anatase titania thin-films were prepared by a modified spray-pyrolysis method. Glass substrates were coated at room temperature with an aerosol-spray of a titania sol-gel solution and then annealed at 500 degrees C to form rough, transparent, crystalline thin-films of anatase TiO2. Silver nanoparticles were deposited on the surface of these films by a photo-assisted deposition method; films were dip-coated in methanolic solutions of silver nitrate salt and then photo-irradiated for 5 h with UVC light. The AgNO3 concentration was adjusted to create an array of films with varying silver loadings. The films displayed photochromism; changing colour to orange-brown in UV-light to colourless under white light. The rates of photochromic change, when subjected to four different lighting conditions (UVC, UVA, white light and dark), were analysed by UV-visible spectroscopy. By assessing the photocatalytic activity to these light sources it was found that the initial photochromic state of the material had a profound effect on the films photocatalytic ability. This effect was more pronounced in the more concentrated silver loaded films; where significant enhancements in photoactivity occurred when reactions were initiated from the photo-reduced state. The mode of improved photocatalysis was attributed to the photo-generated electron trapping by silver nanoparticles, which stabilised photo-generated holes and drove photo-oxidation processes. We believe this is the first study in which the relationship between the photochromic state of a thin-film and its subsequent photocatalytic activity is reported