The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Rachid Mahiou - One of the best experts on this subject based on the ideXlab platform.
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Towards rare-earth-free white light-emitting diode devices based on the combination of dicyanomethylene and pyranine as organic dyes supported on zinc single-layered hydroxide
Beilstein Journal of Nanotechnology, 2019Co-Authors: Rachid MahiouAbstract:A new luminescent composite film resulting from the dispersion of luminescent organic dyes in a single-layered hydroxide (SLH)type inorganic matrix has been developed. Two fluorescent organic dyes emitting visible light upon blue LED excitation were investigated in this study: dicyanomethylene (DCM) and pyranine (HPTS). These dyes exhibit broad emission bands that cover a large part of the visible spectrum. The concept developed in our work consisted in keeping SLH in its wet form to ensure a good dispersion of the fluorescent dyes prior to immobilizing the hybrid materials in a Silicone Polymer to achieve luminescent composite films. We demonstrate that these coatings stacked upon each other and placed above a blue LED lead to white-light emission with suitable photometric parameters for applications in lighting or display devices: colour temperature of 5409 K and colour rendering index (CRI) of 81.
Ivan P Parkin - One of the best experts on this subject based on the ideXlab platform.
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photosensitisation studies of Silicone Polymer doped with methylene blue and nanogold for antimicrobial applications
RSC Advances, 2015Co-Authors: Melissa J Bovis, Sacha Noimark, Josephine H Woodhams, Christopher W M Kay, Jonathan Weiner, William J Peveler, Annapaula Correia, Michael Wilson, Elaine Allan, Ivan P ParkinAbstract:Photosensitisation of Polymers has important potential clinical applications such as the prevention of catheter-associated urinary tract infections (CAUTIs). Polymers incorporated with methylene blue (MB) and 2 nm gold nanoparticles (AuNPs) are effective in killing bacteria at the surface following low power visible illumination. Studies of medical-grade Silicone Polymer samples including segments from urinary catheters were carried out to investigate the generation of reactive oxygen species and the involvement of Type 1 and 2 mechanisms. Singlet oxygen was observed using direct phosphorescence detection and hydroxyl radical generation using electron paramagnetic resonance (EPR) spectroscopy; we conclude that both Type 1 and 2 mechanisms can operate with Polymeric photosensitisation. Transmission electron microscopy (TEM) directly demonstrated the incorporation of AuNPs at the surface of the Silicone. Using Silicone doped with MB AuNPs, a ≥3 log10 reduction in the number of viable Staphylococcus epidermidis bacteria was achieved when exposed to low power laser light; prior sterilisation with ethylene oxide (EO) had no influence on efficacy.
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a general method for the incorporation of nanoparticles into superhydrophobic films by aerosol assisted chemical vapour deposition
Journal of Materials Chemistry, 2013Co-Authors: Colin R Crick, Joseph C Bear, Paul Southern, Ivan P ParkinAbstract:A general method for the synthesis of a novel class of superhydrophobic Polymer thin films with embedded nanoparticles is presented. These materials combine the superhydrophobic nature of Silicone Polymer matrices and the properties of the nanoparticles for photocatalysis, magnetic applications, or high surface area catalysis. The films themselves are deposited using a one-pot aerosol assisted chemical vapour deposition (AACVD) process, and are characterised using electron microscopy, X-ray dispersive spectroscopy, water contact angle and bouncing measurements and elemental mapping. We show that these materials demonstrate multifunctional behaviour through magnetic, catalytic and superhydrophobic measurements.
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Antimicrobial activity of methylene blue and toluidine blue O covalently bound to a modified Silicone Polymer surface
J MATER CHEM, 2009Co-Authors: Ivan P ParkinAbstract:Methylene Blue or Toluidine Blue O were covalently bound to an activated Silicone Polymer by means of an amide condensation reaction. UV-visible absorption spectra confirmed that the dye was surface bound. The new Polymers with covalently attached dye display significant bactericidal activity against Escherichia coli and Staphylococcus epidermidis with a 99.999% reduction in viable bacteria after four minutes exposure to a low power laser.
Kim F. Hayes - One of the best experts on this subject based on the ideXlab platform.
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application of sieve tray air strippers to the treatment of surfactant containing wastewaters
Aiche Journal, 2001Co-Authors: Tohren C G Kibbey, Kurt D Pennell, Kim F. HayesAbstract:Using sieve-tray air stripping as a means of removing contaminants from surfactant solutions was studied to determine if tray air stripping can be applied successfully to treating surfactant-containing wastewaters and, if so, to develop a quantitative approach for designing tray air-stripping systems for treating surfactant-containing wastewaters. High-concentration surfactant solutions were prepared and contaminated with five different volatile organic compounds. Removal of the organic compounds was evaluated using a commercial sieve-tray air stripper. Overall, the air stripper was able to efficiently remove the contaminants from solution, and correction of Henry's Law constants for micellar solubilization-induced volatility reduction allowed tray air-stripper design equations to quantitatively predict air-stripper removal for all contaminants. Foaming within the air stripper could be controlled with low concentrations of a Silicone-Polymer antifoaming agent. Although adding antifoaming agents may be undesirable for some applications, other applications can benefit from the operational and performance advantages of sieve-tray air strippers. Issues related to air-stripper design for low-volatility compounds are also discussed.
Yibing Cheng - One of the best experts on this subject based on the ideXlab platform.
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thermal stability and flammability of Silicone Polymer composites
Polymer Degradation and Stability, 2006Co-Authors: Laura Georgeta Hanu, George P Simon, Yibing ChengAbstract:Abstract Silicone Polymer composites filled with mica, glass frit, ferric oxide and/or a combination of these were developed as part of a ceramifiable Polymer range for electrical power cables and other high temperature applications. This paper reports on the thermal stability of Polymer composites as determined by thermogravimetric techniques, thermal conductivity and heat release rate as measured by cone calorimetry. The effects of fillers on thermal stability and flammability of Silicone Polymer are investigated. Of the fillers studied, mica and ferric oxide were found to have a stabilising effect on the thermal stability of Silicone Polymer. Additionally, mica and ferric oxide were found to lower heat release rates during combustion, but only mica was found to increase time to ignition.
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preferential orientation of muscovite in ceramifiable Silicone composites
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2005Co-Authors: Laura Georgeta Hanu, George P Simon, Yibing ChengAbstract:Abstract Silicones are well known for their thermal stability but are reduced to a powdery ceramic residue with little inherent strength when exposed to elevated temperatures. This limits applications where residue strength may be of importance. Muscovite has been shown to improve the thermal stability of Silicone Polymer and the strength of the resultant ceramic residue upon pyrolysis in air up to 1100 °C. XRD and SEM studies confirm the influence of particle-size and orientation dependencies of muscovite fillers within the Polymer matrix on the resulting eutectic reaction and solidification process, which lead to an improvement in the ultimate strength of the ceramic residue.
Tohren C G Kibbey - One of the best experts on this subject based on the ideXlab platform.
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application of sieve tray air strippers to the treatment of surfactant containing wastewaters
Aiche Journal, 2001Co-Authors: Tohren C G Kibbey, Kurt D Pennell, Kim F. HayesAbstract:Using sieve-tray air stripping as a means of removing contaminants from surfactant solutions was studied to determine if tray air stripping can be applied successfully to treating surfactant-containing wastewaters and, if so, to develop a quantitative approach for designing tray air-stripping systems for treating surfactant-containing wastewaters. High-concentration surfactant solutions were prepared and contaminated with five different volatile organic compounds. Removal of the organic compounds was evaluated using a commercial sieve-tray air stripper. Overall, the air stripper was able to efficiently remove the contaminants from solution, and correction of Henry's Law constants for micellar solubilization-induced volatility reduction allowed tray air-stripper design equations to quantitatively predict air-stripper removal for all contaminants. Foaming within the air stripper could be controlled with low concentrations of a Silicone-Polymer antifoaming agent. Although adding antifoaming agents may be undesirable for some applications, other applications can benefit from the operational and performance advantages of sieve-tray air strippers. Issues related to air-stripper design for low-volatility compounds are also discussed.