Download or read book Att nuation de la toxicit des nanotubes de carbone gr ce la fonctionnalisation chimique written by Menard-moyon and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Noncovalent Functionalization of Carbon Nanotubes written by Claudia Backes and published by Springer Science & Business Media. This book was released on 2012-02-07 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, Claudia Backes guides the reader through her multidisciplinary research into the non-covalent functionalization of carbon nanotubes in water. Although one of the most remarkable materials of the 21st century, carbon nanotubes often have limited application because of their intrinsically low solubility and polydispersity. The author shows that rational surfactant design is a powerful tool for chemists because it can unmask the key to solubilization and allow us to tailor nanotube surface and optical properties in a fully reversible fashion. Aspects of organic, physical and analytical chemistry, as well as colloidal sciences are covered in this outstanding work which brings us one step closer to exploiting this super-material to its full potential.

Download or read book Solubilisation et fonctionnalisation covalente des nanotubes de carbone et autres formes de carbone nanostructur es written by Damien Voiry and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les nanotubes de carbone ou le graphène sont des formes allotropiques du carbone prometteuses pour un large domaine d'applications, mais des modifications de leur surface carbonée sont nécessaires pour leur manipulation et mise en forme. La fonctionnalisation covalente est un des moyens utilisés avec succès dans ce cadre, même si les modifications induites ne sont pas contrôlables. Les travaux réalisés au cours de cette thèse concernent l'utilisation de la réduction chimique des nanotubes et autres nanoformes de carbone, nanocornes, graphène ou nanodisques, pour d'une part obtenir des solutions stables et concentrées dans une gamme de solvants dépendant du type de nanoforme et d'autre part fonctionnaliser de manière covalente les différents types de surface carbonée de ces objets. Dans le cas des nanotubes, des molécules acceptrices ou donneuses d'électrons ont ainsi été greffées permettant la formation d'ensembles donneur-accepteur. D'autre part, le nombre de fonctions chimique greffées a pu être contrôlé, préservant ainsi les propriétés électroniques des nanotubes.

Download or read book Synth se et tude des propri t s m somorphes d espaceurs pour la fonctionnalisation des nanotubes de carbone written by Loïc Louise and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Du fait de leurs exceptionnelles propriétés, un très vaste champ d'applications s'ouvre aux nanotubes de carbone. La connaissance de leur toxicité est un enjeu primordial afin de connaître les risques et les dangers que ces objets représentent.Le travail présenté dans cette thèse vise à la synthèse de dérivés ayant pour but de favoriser les interactions entre les nanotubes et le milieu vivant.La synthèse d'une série de dérivés du cholestérol utilisables pour la fonctionnalisation des nanotubes de carbone a été mise au point. L'utilisation de tels dérivés a pour but de favoriser les interactions entre les objets greffés et les membranes cellulaires.Par ailleurs, de nombreux intermédiaires de synthèse présentent des propriétés mésomorphes. Celles-ci ont été étudiées au moyen de différentes méthodes telles que la microscopie optique, la calorimétrie différentielle à balayage et la diffusion des rayons X.Des nanotubes HiPco ont pu être purifiés et fonctionnalisés. L'analyse de leur cytotoxicité a été abordée, celle-ci a permis de mettre en avant une diminution de la toxicité des nanotubes greffés comparée à celles de nanotubes purifiés.

Download or read book Purification et fonctionnalisation d chantillons de nanotubes de carbone mono feuillets written by Guillaume Mercier and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: La mise en évidence des nanotubes de carbone mono-feuillets (SWCNTs) en 1993 par S. Iijima a été une des découvertes qui a marqué la recherche dans le domaine des nanos. L'étude de leurs propriétés a révélé qu'elles étaient supérieures à celles de matériaux déjà connus et a laissé entrevoir un champ très large d'applications potentielles. Les méthodes de synthèse actuelles permettent de produire des SWCNTs en grande quantité. Cependant, les échantillons de SWCNTs peuvent être hétérogènes tant au niveau de leur composition (impuretés carbonées et métaux catalytiques) qu'en ce qui concerne les caractéristiques des SWCNTs eux-mêmes. Des traitements post-synthèses sont donc indispensables pour améliorer les caractéristiques des échantillons. Dans ce travail, nous avons dans un premier temps mis en oeuvre une procédure de purification (multi-étape) couramment utilisée. En accord avec la littérature, l'optimisation des paramètres expérimentaux notamment en ce qui concerne le traitement d'oxydation n'a pas permis d'obtenir de bons rendements de purification et une sélectivité de réaction performante. Une méthode de purification alternative a été développée. Elle consiste essentiellement à un traitement thermique sous flux de dichlore. Elle a permis de diminuer significativement la proportion d'impuretés métalliques tout en préservant les nanotubes. Elle s'est également révélée efficace avec des échantillons produits selon différentes méthodes. L'autre difficulté majeure dans l'utilisation des nanotubes est leur processabilité. La modification de l'état de surface des nanotubes passe par la fonctionnalisation chimique. Pour cela, nous avons étudié le greffage de fonctions sondes.

Download or read book Defects and Diffusion in Carbon Nanotubes written by and published by . This book was released on 2014 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes are one of the newest materials to be discovered, being barely 20 years old. They are also the most promising one, with one particular sample of multi-walled nanotube attaining a tensile strength of 63GPa, and with carbon nanotubes in general having a specific strength of up to 48000kNm/kg: effectively a direct exploitation of the covalent sp2 bonding between carbon atoms. Plastic deformation begins at about 5% strain. The nanotubes can be produced in lengths of up to 550mm, and thicknesses as small as 4.3Å; making them perfect reinforcement fibres for composites. They also have many other properties which may be useful in electronics, gas storage, etc. The present compilation focuses on the various characteristic types of defect which are found in carbon nanotubes, plus the relatively limited number of diffusion studies which have been performed. The 418 entries cover the period from 1994 to 2014. Keyword: carbon nanotube Abstracts of 418 articles published in a wide range of technical journals coverfirst defects in carbon nanotubes then the diffusion of various compounds through carbon nanotubes. Those on defects consider such aspects as adsorption, characterization, disclination, the effect on compressive behavior, the effect on thermal conductivity, heptagon, interstitial, pinhole, topological, andvacancy. Among the chemicals addressed in the diffusion studies are alkanes, gold, carbon dioxide, copper, iron, water, Lennard-Jones fluid, nitrogen, silicon, and simple gases. -- Carbon-- Engineering-- Materials science.

Download or read book Flexoelectricity in Liquid Crystals written by Agnes Buka and published by World Scientific. This book was released on 2013 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book intends to give a state-of-the-art overview of flexoelectricity, a linear physical coupling between mechanical (orientational) deformations and electric polarization, which is specific to systems with orientational order, such as liquid crystals. Chapters written by experts in the field shed light on theoretical as well as experimental aspects of research carried out since the discovery of flexoelectricity. Besides a common macroscopic (continuum) description the microscopic theory of flexoelectricity is also addressed. Electro-optic effects due to or modified by flexoelectricity as well as various (direct and indirect) measurement methods are discussed. Special emphasis is given to the role of flexoelectricity in pattern-forming instabilities. While the main focus of the book lies in flexoelectricity in nematic liquid crystals, peculiarities of other mesophases (bent-core systems, cholesterics, and smectics) are also reviewed. Flexoelectricity has relevance to biological (living) systems and can also offer possibilities for technical applications. The basics of these two interdisciplinary fields are also summarized.

Download or read book Physical Properties of Amorphous Materials written by David Adler and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Institute for Amorphous Studies was founded in 1982 as the international center for the investigation of amorphous mate rials. It has since played an important role in promoting the und er standing of disordered matter in general. An Institute lecture series on "Fundamentals of Amorphous Materials and Devices" was held during 1982-83 with distinguished speakers from universities and industry. These events were free and open to the public ,and were attended by many representatives of the scientific community. The lectures themselves were highly successful inasmuch as they provided not only formal instruction but also an opportunity for vigorous and stimulating debate. That last element could not be captured within the pages of a book I but the lectures concentrated on the latest advances in the field I which is why their essential contents are he re reproduced in collective form. Together they constitute an interdisciplinary status report of the field. The speakers brought many different viewpoints and a variety of back ground experiences io bear on the problems involved I but though language and conventions vary I the essential unity of the concerns is very clear I as indeed are the ultimate benefits of the many-sided approach.

Download or read book Nonlinear Optical Materials written by Jerome V. Moloney and published by Springer Science & Business Media. This book was released on 1998-08-13 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical methods play a significant role in the rapidly growing field of nonlinear optical materials. This volume discusses a number of successful or promising contributions. The overall theme of this volume is twofold: (1) the challenges faced in computing and optimizing nonlinear optical material properties; and (2) the exploitation of these properties in important areas of application. These include the design of optical amplifiers and lasers, as well as novel optical switches. Research topics in this volume include how to exploit the magnetooptic effect, how to work with the nonlinear optical response of materials, how to predict laser-induced breakdown in efficient optical devices, and how to handle electron cloud distortion in femtosecond processes.