Nanoparticles polymer-modified

Electrocatalysis with Electron-Conducting Polymers Modified by Noble Metal Nanoparticles... 

Different electron-conducting polymers (polyaniline, polypyrrole, polythiophene) are considered as convenient substrates for the electrodeposition of highly dispersed metal electrocatalysts. The preparation and the characterization of electronconducting polymers modified by noble metal nanoparticles are first discussed. Then, their catalytic activities are presented for many important electrochemical reactions related to fuel cells oxygen reduction, hydrogen oxidation, oxidation of Cl molecules (formic acid, formaldehyde, methanol, carbon monoxide), and electrooxidation of alcohols and polyols. 

PREPARATION OF ELECTRON-CONDUCTING POLYMER MODIFIED BY NOBLE METAL NANOPARTICLES... 

Fig. 3 Formation of the core-shell type hydrogel nanoparticles by electrostatic interactions. The anionic solution which contains core polymer is introduced as a mist into a cationic solution of shell polymer. (Modified from Ref. l)...

Kim BJ et al (2006) Effect of areal chain density on the location of polymer-modified gold nanoparticles in a block copolymer template. Macromolecules 39(12> 4108—4114... 

C. Lamy and J.M. Leger, Electrocatalysis with electron conducting polymers modified by noble metal nanoparticles. In Catlysis and Electrocatalysis at Nanoparticle Surfaces, ed. A. Vieckowski, E. Saviniva, and C. Vayenas, Marcell Dekker, New York, 2003. 

Cobalt nanoparticles (surface modified with L-cysteine ethyl ester) ethanol wet are available as 10mn black powder (wet with EtOH) which is best used within 3 months. The material can be easily transferred into stable aqueous suspensions, and can be used as a starting material for surface modifications (e.g. dextran coating) or the preparation of magnetic polymer microspheres. 

Numerous electrochemical platforms have been developed for DNA detection, including direct electrochemistry of the DNA bases [5], electrochemistry of different polymer-modified screen-printed chips [6], electrochemistry of DNA-specific redox indicator molecules or enzymes [7,8], electrochemistry of signal amplification with nanoparticles (NPs) such as gold, silver or magnetic particles [9,10], and dsDNA r-stacked mediated charge transport chemistry [4, 7,11,12]. 

To conclude it can be said that composites of CPs and metal nanoparticles permit a facile flow of electronic charges across the polymer matrix as metallic nanoparticles are dispersed well into the matrix of polymers [88]. Therefore, through a suitable combination of CPs and metal nanoparticles, newly modified surfaces can be generated with higher surface area and enhanced catalytical/electrocatalytic activities [89]. 

Marla, K. T. and Meredith, J. C. 2006. Simulation of interaction forces between nanoparticles End-grafted polymer modifiers. Journal of Chemical Theory and Computation 2 1624 1631. 

Zaharescu, T., Jipa, S., Supaphol, P. Thtamal stability of isotactic polypropylene modified with CaCOa nanoparticles. Polym. Bull. 64, 783-790 (2010)... 

In 2012, Liu et al. prepared polymer-modified PEDOT PSS via a layer-by-layer assembly method. The negatively charged PEDOTrPSS nanoparticles (Figure 9.4A) were first coated with positively charged poly(allylamine... 

Electrochemistry Thermodynamics and Electrified Interfaces, Vol 10 In Situ Imaging Interfadal Kinetics and Mass Transport, Vol 10 Electrochemical Nucleation and Growth Interfacial Kinetics and Mass Transport, Vol 10 Electrodeposition of nanoparticles Interfacial Kinetics and Mass Transport, Vol 10 Electrochemical AFM Instrumentation and Electroanalyt-ical Chemistry, Vol 10 Layer-by-layer Assemblies of Thin Films on Electrodes Modified Electrodes, Vol 10 Organic Polymer Modified Electrodes Modified Electrodes, Vol 10 AFM, In Situ Methods Modified Electrodes, Vol 10. 

Research on oral liposomal delivery systems has moved forward with the development of polymer-modified liposomes. For example, targeted PEGylated liposomes furnished with folic acid for oral delivery were promising, showing enhanced permeability of dextran (used as a marker) across Caco-2 cell monolayers (Anderson et al., 1999). PEG and chitosan-coated lipid nanoparticles were constmcted as oral delivery systems for salmon calcitonin (sCT). The PEG-coated nanoparticles did not alter the transepithelial electrical resistance of Caco-2 cell monolayers, while the chitosan-coated nanoparticles showed a dose-dependent increase in the permeability of dextran across the monolayers (Garcia-Fuentes et al., 2005). It demonstrated that the favourable interaction of the chitosan-coated nanoparticles with intestinal mucosa, together with their permeation enhancing characteristics, could improve the oral absorption of sCT. 

In 1995, Natan et al. reported that Au and Ag nanoparticles adsorbed onto an organosilane-polymer-modified Si substrate could be used as a SERS-active substrate [97]. Subsequently, in 2001 the same authors [98] proposed a novel approach based on the self-assembled monolayer technique which allows the preparation of regularly arranged monodispersed colloidal Au and Ag nanoparticles on functionalized metal or glass substrates. It is now possible to synthesize or fabricate metal nanostructures of various shapes and sizes with a narrow size distribution. Nanoparticles assembled on an electrically conductive substrate can significantly improve the surface uniformity of the EC-SERS substrate. Therefore, use of nanoparticle sols or assembled nanoparticles as SERS substrates has expanded very rapidly during recent years [92]. 

Morral-Rufz G, Melgar-Lesmes P, Garcfa ML, Solans C, Garcfa-Cehna MJ. Design of biocompatible surface-modified polyurethane and polyurea nanoparticles. Polymer 2012 53(26) 6072-80. 

Quinones JP, et al. Self-assembled nanoparticles of modified-chitosan conjugates for the sustained release of DL-a-tocopherol. Carbohydr Polym. 2012 92(l) 856-64. 

Quinones JP, Gothelf KV, Kjems J, Caballero AMH, Schmidt C, Covas CP. N, 06-partially acetylated chitosan nanoparticles hydrophobically-modified for controlled release of steroids and vitamin E. Carbohydr Polym. 2013 91(1) 143-51. 

A. Laachachi, E. Leroy, M. Cochez, M. Ferriol, and J. M. Lopez-Cuesta, Thermal degradation and flammability of poly(methyl methacrylate) containing T1O2 nanoparticles and modified montmorillonite. In Fire and Polymers, A.C.S. Symposium Series... 

We have shown that by various physicochemical methods it is possible to nanostructure bulk polymers in the shape of nanoparticles, that in the case of amorphous polymers, have spherical shape. If the original bulk polymer is able to crystaUize, the shape of the nanoparticle is modified by the process of crystallization. However, it is possible to limit the size of the crystal due to the confinement imposed by the nanoparticle shape. 

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