Search results for " modifica"
showing 10 items of 817 documents
Polythiophene S,S dioxides: an investigation on electrochemical doping
2000
Abstract A new strategy for functionalizing oligothiophenes is the transformation of the thienyl sulphurs into the corresponding S,S dioxides, with the effect of lowering the LUMO energy without significantly affecting the HOMO one. From a quinquethiophene S,S dioxide derivative, a polymer (pQTDO) which can be reversibly n-doped at not very negative potentials still maintaining the property of being p-doped at moderate potential values was electrosynthesized. There is, however, a great difference in the ability to store charge of the polymer’s p- and n-doped forms: a great amount of injected negative charge irreversibly modifies the structure of pQTDO.
Modified Donnan phenomena in polyaniline with poly(vinyl sulphonate) chains
1993
We develop a physical model, based on the modified Donnan phenomena ideas introduced previously by the authors, to describe the acid doping of the conducting polymer polyaniline. The theory is motivated by the experimental work of Asturias et al. [Ber. Bunsenges. Phys. Chem. 95, 1381 (1991)]. Good agreement between theory and experiment is found.
Optical planar Bragg grating sensor for real-time detection of benzene, toluene and xylene in solvent vapour
2012
Abstract We report on an optical planar Bragg grating sensor functionalized by a comparatively simple method to detect substances such as benzene, toluene and xylene (BTX). The functionalization is performed by allyl substituted γ -cyclodextrin derivatives which are immobilized on the sensor surface by dip coating. Our results prove the capability of this functionalized sensor system to detect lowest concentrations of BTX in solvent vapour in real-time with a sensitivity of 3±0.4 pm/100 ppm for benzene, 8±1 pm/100 ppm for toluene and 32±1 pm/100 ppm for m-xylene. Taking into account the spectral resolution and repeatability of the interrogation system this corresponds to a minimum concentra…
Host-guest interactions for extracting antibiotics with a γ-cyclodextrin poly(glycidyl-co-ethylene dimethacrylate) hybrid sorbent
2021
Abstract A procedure for the solid-phase extraction of antibiotics (enoxacin, ofloxacin, norfloxacin, ciprofloxacin, and sparfloxacin) in water has been developed. The sorbent used is based on a poly(glycidyl-co-ethylene dimethacrylate) network, whose previously modified surface has been functionalized with γ-cyclodextrin through a click-chemistry reaction. The architecture of the material has been characterized by thermogravimetric analysis, N2 adsorption-desorption, Raman spectroscopy, confocal microscopy, and scanning electron microscopy, showing good capability to be used as a filler for extraction cartridges. The optimization of the extraction methodology shows good intra-day and inter…
Carbohydrate nanocarriers in biomedical applications: functionalization and construction
2015
The specific targeting of either tumor cells or immune cells in vivo by carefully designed and appropriately surface-functionalized nanocarriers may become an effective therapeutic treatment for a variety of diseases. Carbohydrates, which are prominent biomolecules, have shown their outstanding ability in balancing the biocompatibility, stability, biodegradability, and functionality of nanocarriers. The recent applications of sugar (mono/oligosaccharides and/or polysaccharides) for the development of nanomedicines are summarized in this review, including the application of carbohydrates for the surface-functionalization of various nanocarriers and for the construction of the nanocarrier its…
Design and evaluation of sensory systems based on amphiphilic anthraquinones molecular receptors
2015
A new paradigm is described that allows one to create different types of sensors: from highly sensitive ones to practical household devices. Our approach relies on modular molecular receptors incorporating an intensely-colored aminoanthraquinone signaling unit equipped with both hydrophilic and hydrophobic modules, the number and size of which being configured in accordance with the targeted analyte and the sought detection method. An important advantage is the compliance with some principles of green chemistry, avoiding the use of toxic organic solvents. The proper functionalization of the anthraquinone scaffold afforded water-soluble chromoinophores capable of quantifying selectively Hg2+…
Mössbauer Spectroscopic Study and Magnetic Investigation of Iron(III) Complexes on a DendrimericBasis
2014
The functionalization of the molecular surface of various dendrimer generations with a phosphorous core and external amine groups is obtained by converting those amine groups into the corresponding imines of salicylaldehyde creating multiple coordination sites for the iron atoms. Treatment with iron(III) chloride yields multinuclear iron(III) complexes on a dendrimeric basis.The obtained multinuclear molecular systems exhibit extremely high total spin values. The influence of the generation growth on this type of coordination compounds is investigated by Mossbauer spectroscopy and SQUID magnetometry.
Light induced charging of polymer functionalized nanorods.
2010
ZnO nanorods were functionalized with new block copolymers containing a hole transporting moiety in one block and a dye and an anchor system in the second block. After functionalization, the ZnO nanorods are well dispersible in organic media and the fluorescence of the dye is quenched. Kelvin probe force microscopy was used to measure changes in electrical potential between the ZnO nanorod and the polymeric corona. Upon light irradiation, potential changes on the order of some tens of millivolts were observed on individual structures. This effect is attributed to light-induced charge separation between the ZnO nanorod and its hole transporting polymeric corona.
In situ forming hydrogels of new amino hyaluronic acid/benzoyl-cysteine derivatives as potential scaffolds for cartilage regeneration
2012
A new chemical strategy is described to link ethylenediamino (EDA) groups to primary hydroxyl groups of hyaluronic acid (HA) and the obtained derivatives have been characterized by 1H-NMR and 13C-NMR analyses. Such HA–EDA derivatives have been exploited to control the functionalization degree in benzoyl-cysteine (BC) groups, chosen as moieties able to allow both self-assembling in aqueous media and an oxidative crosslinking. In particular, the kinetics of oxidation of thiol groups in HA–EDA–BC derivatives has been studied in Dulbecco's Phosphate Buffer Solution (DPBS) pH 7.4 by colorimetric assays and rheological measurements. Mechanical properties of chemical hydrogels obtained after oxida…
Covalently bonded layer-by-layer assembly of multifunctional thin films based on activated esters.
2009
We demonstrate that chemically stable, multifunctional polymer thin films can be obtained using the layer-by-layer (LbL) deposition based on covalent bonds between adsorbing chains. Poly(pentafluorophenyl-4-vinylbenzoate) (P1) or poly(pentafluorophenylacrylate) (P2) polymers were assembled with poly(allyl amine) (PAAm) to yield LbL multilayer films through amide bond formation by the reaction between activated esters of P1 or P2 and amine groups in PAAm, which was quantitatively monitored by Fourier transform infrared spectroscopy (FT-IR). It was found that the difference in the solubility of P1 and P2 against ethanol, which was used as the solvent for PAAm, during the LbL deposition yields…