Search results for " modifica"
showing 10 items of 817 documents
Supported Ionic Liquids: A Versatile and Useful Class of Materials.
2017
Supported ionic liquids (SILs) represent a class of materials with peculiar properties and a huge potential regarding their possible applications in different fields of chemistry. Herein, we report our ongoing research about the use of SILs as support for organocatalysts, their role as catalysts themselves, and their application as support and stabilizers of palladium nanoparticles (PdNPs). The use of SILs based materials allowed achieving good results. Moreover, in some cases, after the functionalization of the catalytic species with an ion-tag moiety, a release and catch approach was employed in order to improve the catalytic activity and to facilitate the recovery of the hybrid system fo…
Microfluidic Fabrication of Physically Assembled Nanogels and Micrometric Fibers by Using a Hyaluronic Acid Derivative
2017
The employ of a hyaluronic acid (HA) derivative, bearing octadecyl (C18) and ethylenediamine (EDA) groups, for microfluidic fabrication of nanogels and microfibers is reported in this study. Two HA-EDA-C18 derivatives (125 and 320 kDa) having ionic strength sensitive properties are synthesized and characterized. The control of the rheological properties of HA-EDA-C18 aqueous dispersions by formation of inclusion complexes with hydroxypropyl-β-cyclodextrins (HPCD) is described. Reversibility of C18/HPCD complexation and physical crosslinking is detected in media with different ionic strength through oscillation frequency tests. HA-EDA-C18 125 kDa is employed for nanogel fabrication. Control …
Grafting Silicone at Room Temperature—a Transparent, Scratch-resistant Nonstick Molecular Coating
2020
Silicones are usually considered to be inert and, thus, not reactive with surfaces. Here we show that the most common silicone, methyl-terminated polydimethylsiloxane, spontaneously and stably bonds on glass-and any other material with silicon oxide surface chemistry-even at room temperature. As a result, a 2-5 nm thick and transparent coating, which shows extraordinary nonstick properties toward polar and nonpolar liquids, ice, and even super glue, is formed. Ten microliter drops of various liquids slide off a coated glass when the sample is inclined by less than 10°. Ice adhesion strength on a coated glass is only 2.7 ± 0.6 kPa, that is, more than 98% less than ice adhesion on an uncoated…
Study the effects of moisture content on the electrical properties of technical textiles by impedance spectroscopy
2012
Application of metal coatings for the functionalization of technical fibres and fabrics faced with influence of moisture on functional properties, e.g., the impedance of the metal coated K-glass fabrics have strong dependence of content absorbed water or moisture. The paper devoted to develop methodology for characterisation functional materials based on fabrics and model for interpretation of the electrical impedance spectra to obtained functional characteristics of technical textile fabrics. Model based on analyses of 3D plot of imaginary part of complex modulus spectra versus sample mass. Methodology helps to control content of adsorbed water in fabric and influence of moisture on the fu…
Cesium-Induced Ionic Conduction through a Single Nanofluidic Pore Modified with Calixcrown Moieties
2017
[EN] We demonstrate experimentally and theoretically a nanofluidic device for the selective recognition of the cesium ion by exploiting host¿guest interactions inside confined geometry. For this purpose, a host molecule, i.e., the amine-terminated p-tert-butylcalix[4]arene-crown (tBuC[4]C¿NH2), is successfully synthesized and functionalized on the surface of a single conical nanopore fabricated in a poly(ethylene terephthalate) (PET) membrane through carbodiimide coupling chemistry. On exposure to the cesium cation, the t-BuC[4]C¿Cs+ complex is formed through host¿guest interaction, leading to the generation of positive fixed charges on the pore surface. The asymmetrical distribution of the…
Influence of nanoporous structure on mechanical strength of aluminium and aluminium alloy adhesive structural joints
2006
The influence of surface treatments on the mechanical strength of adhesive joints was investigated. The attention was focused on AA2024 alloy because it is extensively used in both the automotive and aerospace industries. Adhesive joints fabricated with pure aluminium were also investigated in order to evidence possible differences in the surface features after identical treatments. Before joining with a commercial epoxy adhesive, metal substrates were subjected to different kinds of treatment and the surfaces were characterized by SEM analysis. The formation of a microporous surface in the AA2024 alloy, upon etching and anodizing, is discussed on the basis of the role of the intermetallic …
Water-soluble carbon nanotubes through sugar azide functionalization
2011
In this work we report a covalent functionalization of pristine single-walled carbon nanotubes (SWCNTs) directly with three sugar azides, 2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl, 2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl or 2,3,4,6-tetra-O-acetyl-β-d-mannopyranosyl azide. Microwave-assisted functionalization was carried out for SWCNTs prepared with the HiPCO method. The as-prepared, new type of sugar-functionalized SWCNTs were analyzed by Raman and IR spectroscopy. Deacetylation of the functionalized tubes by sodium methoxide yielded nitrogen-linked, sugar-functionalized carbon nanotubes (CNTs) that formed stable dispersions in water. Reactivity of the sugar azides towards SWCNTs was es…
Enhancement of the sub-band-gap photoconductivity in ZnO nanowires through surface functionalization with carbon nanodots
2018
We report on the surface functionalization of ZnO nanowire (NW) arrays by attachment of carbon nanodots (C-dots) stabilized by polyethylenimine. The photoconductive properties of the ZnO NWs/C-dots devices were investigated under photoexcitation with photon energies below and above the ZnO band gap. The results indicate an increased photoresponse of the functionalized devices in the visible spectral range, as well as enhanced UV photoconductivity. This is attributed to the fast injection of photoexcited electrons from the C-dots into the conduction band of the ZnO NWs, and the subsequent slower desorption of molecular species from the NW surface, which reduces the surface depletion region i…
Plasma Electrolytic Oxidation of TiZr Alloy in ZnONPs-Contained Solution: Structural and Biological Assessment
2020
Titanium (Ti) and its alloys with zirconium (Zr) due of their biological safety, lower elastic modulus and excellent corrosion resistance are the most attractive metallic materials for medical applications. Plasma electrolytic oxidation (PEO) is an environment-friendly process with rapid deposition of anodic oxide coating on the implant surface. PEO coating can incorporate different nanoparticles (NPs) into implant surface such as ZnO that stimulates osteoblast proliferation and mineralization, possesses antibacterial ability. The aim of current research was to evaluate structural and chemical properties of TiZr-alloy with addition ZnO NPs after the PEO in Ca/P solution. The alloy of the Ti…
Tailoring the stealth properties of biocompatible polysaccharide nanocontainers.
2014
Fundamental development of a biocompatible and degradable nanocarrier platform based on hydroxyethyl starch (HES) is reported. HES is a derivative of starch and possesses both high biocompatibility and improved stability against enzymatic degradation; it is used to prepare nanocapsules via the polyaddition reaction at the interface of water nanodroplets dispersed in an organic miniemulsion. The synthesized hollow nanocapsules can be loaded with hydrophilic guests in its aqueous core, tuned in size, chemically functionalized in various pathways, and show high shelf life stability. The surface of the HES nanocapsules is further functionalized with poly(ethylene glycol) via different chemistri…