Search results for "Surface coating"
showing 10 items of 44 documents
Coordinative Binding of Polymers to Metal-Organic Framework Nanoparticles for Control of Interactions at the Biointerface
2019
Metal-organic framework nanoparticles (MOF NPs) are of growing interest in diagnostic and therapeutic applications, and due to their hybrid nature, they display enhanced properties compared to more established nanomaterials. The effective application of MOF NPs, however, is often hampered by limited control of their surface chemistry and understanding of their interactions at the biointerface. Using a surface coating approach, we found that coordinative polymer binding to Zr- fum NPs is a convenient way for peripheral surface functionalization. Different polymers with biomedical relevance were assessed for the ability to bind to the MOF surface. Carboxylic acid and amine containing polymers…
Selective modification of the band gaps of GaInNas/GaAs structures by quantum well intermixing techniques
2003
We report the unambiguous demonstration of controlled quantum well intermixing (QWI) in the technologically important GaInNAs/ GaAs 1.3 mum material system. QWI is a key technique to selectively modify the band gap of quantum wells, which has found broad application in semiconductor lasers and photonic integrated circuits (PICs). Extending such technology to GaInNAs/GaAs structures is highly desirable due to the technologically advantageous properties of this material system. Here, we investigate well-characterized GaInNAs quantum well material which has been annealed "to saturation" before QWI processing to allow unambiguous interpretation of results. After RTA at 700 degreesC for similar …
Deactivation of ice nuclei due to atmospherically relevant surface coatings
2009
The ice nucleation characteristics of Arizona test dust (ATD) and illite clay, surrogates for atmospheric ice nuclei, have been determined at the Aerosol Interactions and Dynamics in the Atmosphere (AIDA) chamber located at the Research Center Karlsruhe in Germany. The objective of this research was to determine the effect of sulfuric acid and ammonium sulfate coatings on the ability of these mineral dust surrogates to nucleate ice in an environment where particles realistically compete for water vapor. Coated ATD particles required higher saturations at all temperatures considered, from −20 to −45 ◦ C, than did identical uncoated particles. Freezing of coated particles often required satur…
Surface preparation influence on the initial stages of MOCVD growth of TiO2 thin films
2006
In situ chemical surface analyses using X-ray photoelectron spectroscopy (XPS), completed by ex situ atomic force microscopy (AFM) analyses, were performed in order to compare the initial stages of MOCVD growth of TiO 2 thin films on two different surface types. The first type was a silicon native oxide free hydrogen terminated surface and the second one was a silicon dioxide surface corresponding to a thin layer of 3.5 nm thick in situ thermally grown on silicon substrate. Si(100) was used as substrate, and the growths of TiO 2 thin films were achieved with titanium tetraisopropoxide (TTIP) as precursor under a temperature of 675 °C, a pressure of 0.3 Pa and a deposition time of 1 h. Whate…
Cooperative Catechol-Functionalized Polypept(o)ide Brushes and Ag Nanoparticles for Combination of Protein Resistance and Antimicrobial Activity on M…
2018
Prevention of biofouling and microbial contamination of implanted biomedical devices is essential to maintain their functionality and biocompatibility. For this purpose, polypept(o)ide block copolymers have been developed, in which a protein-resistant polysarcosine (pSar) block is combined with a dopamine-modified poly(glutamic acid) block for surface coating and silver nanoparticles (Ag NPs) formation. In the development of a novel, versatile, and biocompatible antibacterial surface coating, block lengths pSar were varied to derive structure-property relationships. Notably, the catechol moiety performs two important tasks in parallel; primarily it acts as an efficient anchoring group to me…
Streptavidin-coated TiO2 surfaces are biologically inert: Protein adsorption and osteoblast adhesion studies
2011
Non-fouling TiO2 surfaces are attractive for a wide range of applications such as biosensors and medical devices, where biologically inert surfaces are needed. Typically, this is achieved by controlled surface modifications which prevent protein adsorption. For example, polyethylene glycol (PEG) or PEG-derived polymers have been widely applied to render TiO2 surfaces biologically inert. These surfaces have been further modified in order to achieve specific bio-activation. Therefore, there have been efforts to specifically functionalize TiO2 surfaces with polymers with embedded biotin motives, which can be used to couple streptavidin for further functionalization. As an alternative, here a s…
Fabrication and characterization of ZnO nanowires/CdSe/CuSCN eta-solar cell
2006
Des cellules solaires extremely thin absorber (eta) ZnO/CdSe/CuSCN a base de nanofils de ZnO ont ete realisees avec succes en utilisant des techniques faciles d'acces de depot en solution et par voie electrochimique. Une couche constituee de nanofils de ZnO monocristallin de plusieurs microns de hauteur et de 100-200 nm de diametre a ete deposee sur un substrat de verre conducteur (SnO 2 :F) recouvert d'une couche de ZnO formee par pyrolyse de spray agissant comme couche electronique bloquante. Une couche mince de 30-40 nm de CdSe jouant le role d'un absorbeur a ete electrodeposee de maniere conforme le long des nanofils de ZnO. Les espaces entre les nanofils composite de ZnO/CdSe ont ete r…
High Temperature Corrosion Behaviour of Coated F17Ti Stainless Steel
1997
Nous avons etudie l'effet de revetements de chromine et d'alumine sur le comportement de l'acier inoxydable F17Ti. Les films ont ete formes a la surface de l'alliage par pyrolyse de la vapeur d'un precurseur organometallique (MOCVD). Cette technique permet egalement de preparer des oxydes d'elements de terres rares. Ceci nous a conduit a envisager la formation de couches barrieres dopees par un element actif, soit par depots successifs, soit par codeposition de chromine ou d'alumine et d'un oxyde de terre rare, suivi d'un traitement de recuit d'homogeneisation. Les revetements ainsi obtenus ont ete caracterises par microscopie electronique a balayage, microanalyse X, diffraction des rayons …
Synthesis, characterization and ethylene polymerization by metallasilsesquioxane
2013
Soluble complexes of group (IV) metallocenes anchored on a substituted polyhedral oligomeric silsesquioxane trisilanol support were prepared and characterized. These catalyst precursors formulated as [M(O^O^O)X] are found to be active in polymerization of ethylene at high temperature in combination with ethylaluminum sesquichloride (Et3Al2Cl3, EASC) as co-catalyst. The polyethylene obtained by these catalysts is linear, crystalline and displays narrow dispersity. The unique low molecular weight PE formed in this reaction exhibits properties comparable to commercial micronized PE waxes that have potential industrial applications in surface coating and ink formulations. Copyright © 2013 John …
Quantitative molecular plating of large-area 242Pu targets with improved layer properties
2015
Abstract For measurements of the neutron-induced fission cross section of 242Pu, large-area (42 cm2) 242Pu targets were prepared on Ti-coated Si wafers by means of constant current density molecular plating. Radiochemical separations were performed prior to the platings. Quantitative deposition yields (>95%) were determined for all targets by means of alpha-particle spectroscopy. Layer densities in the range of 100–150 μg/cm2 were obtained. The homogeneity of the targets was studied by radiographic imaging. A comparative study between the quality of the layers produced on the Ti-coated Si wafers and the quality of layers grown on normal Ti foils was carried out by applying scanning electron…