Search results for "surface modification"
showing 10 items of 417 documents
Synthesis of silacyclopent-2-en-4-ols via intramolecular [2 + 2] photocycloaddition of benzoyl(allyl)silanes
2019
Organosilicon compounds are versatile units with a wide range of uses from medicinal chemistry to the field of organic electronics. An unprecedented method for the synthesis of novel diaryl-substituted silacyclopentenols via blue-light promoted intramolecular [2 + 2] photocycloaddition of acyl silanes is herein disclosed. Additionally, the present findings demonstrate the influence of the olefin substituents in controlling the regioselectivity of the intramolecular Paterno–Buchi reaction, providing silacycles different from previously reported ones. The high degree of functionalization of these compounds makes them attractive precursors to other synthetically challenging silacyclopentanes.
Effects of functionalized carbon nanotubes in peroxide crosslinking of diene elastomers
2009
Abstract The crosslinking reaction of ethylene–propylene–diene terpolymer (EPDM) peroxide vulcanization filled with pristine and functionalized carbon nanotubes (CNTs and S/CNTs) was evaluated by rheometric tests. The functionalization of CNTs was carried out by diazonium salt methodology in acid medium. S/CNTs were characterised by means of TGA, EDX, Raman and elemental analysis. Pristine CNTs were found to gradually increase the delta torque as a function of loading fraction. Nevertheless, the vulcanization time, scorch and optimum cure time hardly varied on addition of CNTs. However, S/CNTs noticeably affected the cure process, reducing the vulcanization time and delta torque. This effec…
Oxazoline functionalization of polyethylenes and their blends with polyamides and polyesters
2001
The compatibilization of blends of polyamide-6 (PA6) with linear low density polyethylene (LLDPE) and of poly(ethylene terephthalate) (PET) with high density polyethylene (HDPE), by functionalization of the polyethylenes with oxazoline groups was investigated. Chemical modification of LLDPE and HDPE was carried out by melt free radical grafting with ricinoloxazoline maleinate. Blends preparation was made either with a two-steps procedure comprising functionalization and blending, and in a single step in which the chemical modification of polyethylene with the oxazoline monomer was realized in situ, during blending. The characterization of the products was carried out by FTIR spectroscopy an…
TiO2/Ag2O immobilized on cellulose paper: A new floating system for enhanced photocatalytic and antibacterial activities
2021
Paper-TiO2-Ag2O floating photocatalysts were produced under mild condition and their photocatalytic activity for the degradation of aromatic amine under sunlight stimulant was investigated. Characterizations by Raman, XRD, XPS, DRS and PL confirmed the presence of TiO2 and Ag2O, and the morphology of the appended TiO2/Ag2O layer was probed by FE-SEM. The photocatalytic activity of the prepared samples was investigated by the degradation of aniline (AN) in water under simulated sun-light illumination and constrained conditions, i.e. non-stirring and non-oxygenation. The presence of Ag2O combined with TiO2 was shown to improve the resistance of paper to bacteria attack, thus increasing the du…
Grafting of hyperbranched polymers: From unusual complex polymer topologies to multivalent surface functionalization
2013
Abstract In this feature article, the grafting of hyperbranched polymers to different substrates is reviewed. Both grafting onto macromolecules with different topologies (homogeneous grafting) and the resulting complex polymer architectures containing highly branched segments as well as their applications are discussed. In the second part grafting of hyperbranched polymers on surfaces, i.e., planar surfaces and spherical particles (heterogeneous grafting), with respect to specific applications, such as bio-repellent surfaces or soluble carbon nanotubes is described. In all cases, the one-step synthesis and the resulting highly branched topology of the hyperbranched building blocks is benefi…
Opportunities and Challenges of Fluorescent Carbon Dots in Translational Optical Imaging
2015
The fluorescent carbon dot (C-dot) is a new class of carbon nanomaterials. It has a discrete or quasispherical structure, typically measures less than 10 nm and contains sp(2)/sp(3) carbon, oxygen/nitrogen-based groups and surface-modified functional groups. Compared with semiconductor quantum dots (QDs), C-dots offer much lower toxicity and a better biocompatibility profile. Their other favorable features include easy and inexpensive synthesis and surface modification potential. C-dots can be morphologically classified into graphene-based quantum dots (GQDs) and amorphous carbon nanodots (ACNDs). Numerous methods have been developed to synthesize C-dots, and are mainly divided into 'top-do…
Molecular Fingerprints of Thyroid Cancer Cells by Using Library of Molecular Receptors Formed by N-Lipidated Peptides Immobilized on Cellulose
2018
This paper presents a novel diagnostic method using a library of molecular receptors to assess the composition of healthy and tumorous tissue samples. Molecular receptors were formed by self-organization of N-lipidated peptides attached in the regular fashion via aminophenylamino-1,3,5-triazine linkers to the surface of a cellulose plate. The library was cloned into multiple, identical copies. A new clone was used in each test. The binding process was monitored by staining the discs with Brilliant Black and quantitative color measure- ment was performed in 256-grade grayscale. Substantial differences in the composition of healthy and tumor samples were observed in most cases. The sharp diff…
A modified guanosine phosphoramidite for click functionalization of RNA on the sugar edge
2012
A propargyl containing guanosine phosphoramidite was synthesized and incorporated into siRNA, enabling click-ligation with an azido fluorophore onto the nucleobase sugar edge. Duplex stability was not affected by labeling at this new site, which allowed deconvolution of the effects of label, structure and attachment site on RNAi activity.
Pathogen-Mimicking MnO Nanoparticles for Selective Activation of the TLR9 Pathway and Imaging of Cancer Cells
2009
Here, design of the first pathogen-mimicking metal oxide nanoparticles with the ability to enter cancer cells and to selectively target and activate the TLR9 pathway, and with optical and MR imaging capabilities, is reported. The immobilization of ssDNA (CpG ODN 2006) on MnO nanoparticles is performed via the phosphoramidite route using a multifunctional polymer. The multifunctional polymer used for the nanoparticle surface modification not only affords a protective organic biocompatible shell but also provides an efficient and convenient means for loading immunostimulatory oligonucleotides. Since fluorescent molecules are amenable to photodetection, a chromophore (Rhodamine) is introduced …
Self-assembled monolayers based spintronics: from ferromagnetic surface functionalization to spin-dependent transport.
2016
Chemically functionalized surfaces are studied for a wide range of applications going from medicine to electronics. Whereas non-magnetic surfaces have been widely studied, functionalization of magnetic surfaces is much less common and has almost never been used for spintronics applications. In this article we present the functionalization of La2/3Sr1/3MnO3, a ferromagnetic oxide, with self-assembled monolayers for spintronics. La2/3Sr1/3MnO3 is the prototypical half-metallic manganite used in spintronics studies. First, we show that La2/3Sr1/3MnO3 can be functionalized by alkylphosphonic acid molecules. We then emphasize the use of these functionalized surfaces in spintronics devices such a…