Literatura académica sobre el tema "PMF glissante"

As the ball dropped on 1999, is it any wonder that No Doubt played, “It’s the End of the World as We Know It” by R.E.M. live on MTV? Any discussion of the Nineties—and its pinnacle moment, Y2K—requires a discussion of both the cover and the glitch, two performative and technological enactments that fomented the collapse between author-reader and user-machine that has, twenty years later, become normalised in today’s Post Internet culture. By staging failure and inviting the audience to participate, the glitch and the cover call into question the original and the origin story. This breakdown of normative borders has prompted the convergence of previously demarcated media, genres, and cultures, a constellation from which to recognise a stochastic hybrid form. The Cover as a Revelation of Collaborative MurmurBefore Sean Parker collaborated with Shawn Fanning to launch Napster on 1 June 1999, networked file distribution existed as cumbersome text-based programs like Internet Relay Chat and Usenet, servers which resembled bulletin boards comprising multiple categories of digitally ripped files. Napster’s simple interface, its advanced search filters, and its focus on music and audio files fostered a peer-to-peer network that became the fastest growing website in history, registering 80 million users in less than two years.In harnessing the transgressive power of the Internet to force a new mode of content sharing, Napster forced traditional providers to rethink what constitutes “content” at a moment which prefigures our current phenomena of “produsage” (Bruns) and the vast popularity of user-generated content. At stake is not just the democratisation of art but troubling the very idea of intellectual property, which is to say, the very concept of ownership.Long before the Internet was re-routed from military servers and then mainstreamed, Michel Foucault understood the efficacy of anonymous interactions on the level of literature, imagining a culture where discourse would circulate without any need for an author. But what he was asking in 1969 is something we can better answer today, because it seems less germane to call into question the need for an author in a culture in which everyone is writing, producing, and reproducing text, and more effective to think about re-evaluating the notion of a single author, or what it means to write by yourself. One would have to testify to the particular medium we have at our disposal, the Internet’s ultimate permissibility, its provocations for collaboration and co-creation. One would have to surrender the idea that authors own anything besides our will to keep producing, and our desire for change; and to modulate means to resist without negating, to alter without omitting, to enable something new to come forward; the unfolding of the text into the anonymity of a murmur.We should remind ourselves that “to author” all the way down to its Latin roots signifies advising, witnessing, and transferring. We should be reminded that to author something means to forget the act of saying “I,” to forget it or to make it recede in the background in service of the other or others, on behalf of a community. The de-centralisation of Web development and programming initiated by Napster inform a poetics of relation, an always-open structure in which, as Édouard Glissant said, “the creator of a text is effaced, or rather, is done away with, to be revealed in the texture of his creation” (25). When a solid melts, it reveals something always underneath, something at the bottom, something inside—something new and something that was always already there. A cover, too, is both a revival and a reworking, an update and an interpretation, a retrospective tribute and a re-version that looks toward the future. In performing the new, the original as singular is called into question, replaced by an increasingly fetishised copy made up of and made by multiples.Authorial Effacement and the Exigency of the ErrorY2K, otherwise known as the Millennium Bug, was a coding problem, an abbreviation made to save memory space which would disrupt computers during the transition from 1999 to 2000, when it was feared that the new year would become literally unrecognisable. After an estimated $300 billion in upgraded hardware and software was spent to make computers Y2K-compliant, something more extraordinary than global network collapse occurred as midnight struck: nothing.But what if the machine admits the possibility of accident? Implicit in the admission of any accident is the disclosure of a new condition—something to be heard, to happen, from the Greek ad-cadere, which means to fall. In this drop into non-repetition, the glitch actualises an idea about authorship that necessitates multi-user collaboration; the curtain falls only to reveal the hidden face of technology, which becomes, ultimately, instructions for its re-programming. And even as it deviates, the new form is liable to become mainstreamed into a new fashion. “Glitch’s inherently critical moment(um)” (Menkman 8) indicates this potential for technological self-insurgence, while suggesting the broader cultural collapse of generic markers and hierarchies, and its ensuing flow into authorial fluidity.This feeling of shock, this move “towards the ruins of destructed meaning” (Menkman 29) inherent in any encounter with the glitch, forecasted not the immediate horror of Y2K, but the delayed disasters of 9/11, Hurricane Katrina, Deepwater Horizon Oil Spill, Indian Ocean tsunami, Sichuan Province earthquake, global financial crisis, and two international wars that would all follow within the next nine years. If, as Menkman asserts, the glitch, in representing a loss of self-control “captures the machine revealing itself” (30), what also surfaces is the tipping point that edges us toward a new becoming—not only the inevitability of surrender between machine and user, but their reversibility. Just as crowds stood, transfixed before midnight of the new millennium in anticipation of the error, or its exigency, it’s always the glitch I wait for; it’s always the glitch I aim to re-create, as if on command. The accidental revelation, or the machine breaking through to show us its insides. Like the P2P network that Napster introduced to culture, every glitch produces feedback, a category of noise (Shannon) influencing the machine’s future behaviour whereby potential users might return the transmission.Re-Orienting the Bizarre in Fantasy and FictionIt is in the fantasy of dreams, and their residual leakage into everyday life, evidenced so often in David Lynch’s Twin Peaks, where we can locate a similar authorial agency. The cult Nineties psycho-noir, and its discontinuous return twenty-six years later, provoke us into reconsidering the science of sleep as the art of fiction, assembling an alternative, interactive discourse from found material.The turning in and turning into in dreams is often described as an encounter with the “bizarre,” a word which indicates our lack of understanding about the peculiar processes that normally happen inside our heads. Dreams are inherently and primarily bizarre, Allan J. Hobson argues, because during REM sleep, our noradrenergic and serotonergic systems do not modulate the activated brain, as they do in waking. “The cerebral cortex and hippocampus cannot function in their usual oriented and linear logical way,” Hobson writes, “but instead create odd and remote associations” (71). But is it, in fact, that our dreams are “bizarre” or is it that the model itself is faulty—a precept premised on the normative, its dependency upon generalisation and reducibility—what is bizarre if not the ordinary modulations that occur in everyday life?Recall Foucault’s interest not in what a dream means but what a dream does. How it rematerialises in the waking world and its basis in and effect on imagination. Recall recollection itself, or Erin J. Wamsley’s “Dreaming and Offline Memory Consolidation.” “A ‘function’ for dreaming,” Wamsley writes, “hinges on the difficult question of whether conscious experience in general serves any function” (433). And to think about the dream as a specific mode of experience related to a specific theory of knowledge is to think about a specific form of revelation. It is this revelation, this becoming or coming-to-be, that makes the connection to crowd-sourced content production explicit—dreams serve as an audition or dress rehearsal in which new learning experiences with others are incorporated into the unconscious so that they might be used for production in the waking world. Bert O. States elaborates, linking the function of the dream with the function of the fiction writer “who makes models of the world that carry the imprint and structure of our various concerns. And it does this by using real people, or ‘scraps’ of other people, as the instruments of hypothetical facts” (28). Four out of ten characters in a dream are strangers, according to Calvin Hall, who is himself a stranger, someone I’ve never met in waking life or in a dream. But now that I’ve read him, now that I’ve written him into this work, he seems closer to me. Twin Peak’s serial lesson for viewers is this—even the people who seem strangers to us can interact with and intervene in our processes of production.These are the moments that a beginning takes place. And even if nothing directly follows, this transfer constitutes the hypothesised moment of production, an always-already perhaps, the what-if stimulus of charged possibility; the soil plot, or plot line, for freedom. Twin Peaks is a town in which the bizarre penetrates the everyday so often that eventually, the bizarre is no longer bizarre, but just another encounter with the ordinary. Dream sequences are common, but even more common—and more significant—are the moments in which what might otherwise be a dream vision ruptures into real life; these moments propel the narrative.Exhibit A: A man who hasn’t gone outside in a while begins to crumble, falling to the earth when forced to chase after a young girl, who’s just stolen the secret journal of another young girl, which he, in turn, had stolen.B: A horse appears in the middle of the living room after a routine vacuum cleaning and a subtle barely-there transition, a fade-out into a fade-in, what people call a dissolve. No one notices, or thinks to point out its presence. Or maybe they’re distracted. Or maybe they’ve already forgotten. Dissolve.(I keep hitting “Save As.” As if renaming something can also transform it.)C: All the guests at the Great Northern Hotel begin to dance the tango on cue—a musical, without any music.D: After an accident, a middle-aged woman with an eye patch—she was wearing the eye patch before the accident—believes she’s seventeen again. She enrolls in Twin Peaks High School and joins the cheerleading team.E: A woman pretending to be a Japanese businessman ambles into the town bar to meet her estranged husband, who fails to recognise his cross-dressing, race-swapping wife.F: A girl with blond hair is murdered, only to come back as another girl, with the same face and a different name. And brown hair. They’re cousins.G: After taking over her dead best friend’s Meals on Wheels route, Donna Hayward walks in to meet a boy wearing a tuxedo, sitting on the couch with his fingers clasped: a magician-in-training. “Sometimes things can happen just like this,” he says with a snap while the camera cuts to his grandmother, bed-ridden, and the appearance of a plate of creamed corn that vanishes as soon as she announces its name.H: A woman named Margaret talks to and through a log. The log, cradled in her arms wherever she goes, becomes a key witness.I: After a seven-minute diegetic dream sequence, which includes a one-armed man, a dwarf, a waltz, a dead girl, a dialogue played backward, and a significantly aged representation of the dreamer, Agent Cooper wakes up and drastically shifts his investigation of a mysterious small-town murder. The dream gives him agency; it turns him from a detective staring at a dead-end to one with a map of clues. The next day, it makes him a storyteller; all the others, sitting tableside in the middle of the woods become a captive audience. They become readers. They read into his dream to create their own scenarios. Exhibit I. The cycle of imagination spins on.Images re-direct and obfuscate meaning, a process of over-determination which Foucault says results in “a multiplication of meanings which override and contradict each other” (DAE 34). In the absence of image, the process of imagination prevails. In the absence of story, real drama in our conscious life, we form complex narratives in our sleep—our imaginative unconscious. Sometimes they leak out, become stories in our waking life, if we think to compose them.“A bargain has been struck,” says Harold, an under-5 bit player, later, in an episode called “Laura’s Secret Diary.” So that she might have the chance to read Laura Palmer’s diary, Donna Hayward agrees to talk about her own life, giving Harold the opportunity to write it down in his notebook: his “living novel” the new chapter which reads, after uncapping his pen and smiling, “Donna Hayward.”He flips to the front page and sets a book weight to keep the page in place. He looks over at Donna sheepishly. “Begin.”Donna begins talking about where she was born, the particulars of her father—the lone town doctor—before she interrupts the script and asks her interviewer about his origin story. Not used to people asking him the questions, Harold’s mouth drops and he stops writing. He puts his free hand to his chest and clears his throat. (The ambient, wind-chime soundtrack intensifies.) “I grew up in Boston,” he finally volunteers. “Well, actually, I grew up in books.”He turns his head from Donna to the notebook, writing feverishly, as if he’s begun to write his own responses as the camera cuts back to his subject, Donna, crossing her legs with both hands cupped at her exposed knee, leaning in to tell him: “There’s things you can’t get in books.”“There’s things you can’t get anywhere,” he returns, pen still in his hand. “When we dream, they can be found in other people.”What is a call to composition if not a call for a response? It is always the audience which makes a work of art, re-framed in our own image, the same way we re-orient ourselves in a dream to negotiate its “inconsistencies.” Bizarreness is merely a consequence of linguistic limitations, the overwhelming sensory dream experience which can only be re-framed via a visual representation. And so the relationship between the experience of reading and dreaming is made explicit when we consider the associations internalised in the reader/audience when ingesting a passage of words on a page or on the stage, objects that become mental images and concept pictures, a lens of perception that we may liken to another art form: the film, with its jump-cuts and dissolves, so much like the defamiliarising and dislocating experience of dreaming, especially for the dreamer who wakes. What else to do in that moment but write about it?Evidence of the bizarre in dreams is only the evidence of the capacity of our human consciousness at work in the unconscious; the moment in which imagination and memory come together to create another reality, a spectrum of reality that doesn’t posit a binary between waking and sleeping, a spectrum of reality that revels in the moments where the two coalesce, merge, cross-pollinate—and what action glides forward in its wake? Sustained un-hesitation and the wish to stay inside one’s self. To be conscious of the world outside the dream means the end of one. To see one’s face in the act of dreaming would require the same act of obliteration. Recognition of the other, and of the self, prevents the process from being fulfilled. Creative production and dreaming, like voyeurism, depend on this same lack of recognition, or the recognition of yourself as other. What else is a dream if not a moment of becoming, of substituting or sublimating yourself for someone else?We are asked to relate a recent dream or we volunteer an account, to a friend or lover. We use the word “seem” in nearly every description, when we add it up or how we fail to. Everything seems to be a certain way. It’s not a place but a feeling. James, another character on Twin Peaks, says the same thing, after someone asks him, “Where do you want to go?” but before he hops on his motorcycle and rides off into the unknowable future outside the frame. Everything seems like something else, based on our own associations, our own knowledge of people and things. Offline memory consolidation. Seeming and semblance. An uncertainty of appearing—both happening and seeing. How we mediate—and re-materialise—the dream through text is our attempt to re-capture imagination, to leave off the image and better become it. If, as Foucault says, the dream is always a dream of death, its purpose is a call to creation.Outside of dreams, something bizarre occurs. We call it novelty or news. We might even bestow it with fame. A man gets on the wrong plane and ends up halfway across the world. A movie is made into the moment of his misfortune. Years later, in real life and in movie time, an Iranian refugee can’t even get on the plane; he is turned away by UK immigration officials at Charles de Gaulle, so he spends the next sixteen years living in the airport lounge; when he departs in real life, the movie (The Terminal, 2004) arrives in theaters. Did it take sixteen years to film the terminal exile? How bizarre, how bizarre. OMC’s eponymous refrain of the 1996 one-hit wonder, which is another way of saying, an anomaly.When all things are counted and countable in today’s algorithmic-rich culture, deviance becomes less of a statistical glitch and more of a testament to human peculiarity; the repressed idiosyncrasies of man before machine but especially the fallible tendencies of mankind within machines—the non-repetition of chance that the Nineties emblematised in the form of its final act. The point is to imagine what comes next; to remember waiting together for the end of the world. There is no need to even open your eyes to see it. It is just a feeling. ReferencesBruns, Axel. “Towards Produsage: Futures for User-Led Content Production.” Cultural Attitudes towards Technology and Communication 2006: Proceedings of the Fifth International Conference, eds. Fay Sudweeks, Herbert Hrachovec, and Charles Ess. Murdoch: School of Information Technology, 2006. 275-84. <https://eprints.qut.edu.au/4863/1/4863_1.pdf>.Foucault, Michel. “Dream, Imagination and Existence.” Dream and Existence. Ed. Keith Hoeller. Pittsburgh: Review of Existential Psychology & Psychiatry, 1986. 31-78.———. “What Is an Author?” The Foucault Reader: An Introduction to Foucault’s Thought. Ed. Paul Rainbow. New York: Penguin, 1991.Glissant, Édouard. Poetics of Relation. Trans. Betsy Wing. Ann Arbor: U of Michigan P, 1997.Hall, Calvin S. The Meaning of Dreams. New York: McGraw Hill, 1966.Hobson, J. Allan. The Dream Drugstore: Chemically Altered State of Conscious­ness. Cambridge: MIT Press, 2001.Menkman, Rosa. The Glitch Moment(um). Amsterdam: Network Notebooks, 2011.Shannon, Claude Elwood. “A Mathematical Theory of Communication.” The Bell System Technical Journal 27 (1948): 379-423.States, Bert O. “Bizarreness in Dreams and Other Fictions.” The Dream and the Text: Essays on Literature and Language. Ed. Carol Schreier Rupprecht. Albany: SUNY P, 1993.Twin Peaks. Dir. David Lynch. ABC and Showtime. 1990-3 & 2017. Wamsley, Erin. “Dreaming and Offline Memory Consolidation.” Current Neurology and Neuroscience Reports 14.3 (2014): 433. “Y2K Bug.” Encyclopedia Britannica. 18 July 2018. <https://www.britannica.com/technology/Y2K-bug>.

Cette thèse a pour objectif le développement d’une famille de commandes adaptatives robustes par modes glissant pour une large classe de systèmes non linéaires incertains et perturbés. Ainsi, deux lois de commande ont été développées. Dans la première, le modèle du système a été reformulé de telle sorte que toutes les dynamiques inconnues soient regroupées dans une seule fonction et ainsi utiliser un seul approximateur. Dans ce contexte, les réseaux d’ondelettes flous ont été d’abord utilisés vus leurs convergences rapides mais ils ne permettent de donner de bons résultats en présence des informations linguistiques incertaines. Afin de remédier à cela, un système flou de type-2 a été utilisé. Pour assurer la robustesse vis-à-vis des perturbations externes, des incertitudes et erreurs d’approximation, le mode glissant a été proposé. Pour réduire les sollicitations au démarrage au niveau du signal de commande, une surface non-linéaire a été introduite. La loi de commande ainsi construite permet d’assurer la robustesse et la stabilité globale du système bouclé tout en éliminant le phénomène de chattering dans le cas du mode glissant classique. Cependant, le choix des gains de la surface de glissement devient compliqué pour des systèmes d’ordre supérieur à 2. Pour résoudre ce problème, une nouvelle loi de commande par mode glissant a été proposée. L’avantage principal de cette approche réside dans le fait que la surface de glissement a été modifiée de telle sorte que la phase d’approche a été supprimée ce qui rend le système plus robuste et augmente sa vitesse de convergence aux signaux de références. .
This thesis aims to develop a family of adaptive robust sliding modes for a large class of non-linear uncertain and disturbed. Two control laws were developed. In the first, the model system has been reformed such that all the unknown dynamics are combined in one function and then use a single approximation. In this context, fuzzy wavelet networks were first used thanks to their rapid convergence but they don’t give good results in the presence of uncertain linguistic information. To resolve this, a fuzzy system of type-2 was used. To ensure robustness against external disturbances, uncertainty and approximation errors, the sliding mode has been proposed. To reduce the stresses at the start of the signal, a non-linear was introduced. The control law is built to ensure the robustness and overall stability of the closed system in addition to it’s capacity of eliminating the phenomenon of chattering in the case of classical sliding mode. However, the choice of the gains of the sliding surface becomes complicated for systems of order greater than 2. To overcome this problem, a new control law using sliding mode has been proposed. The main advantage of this approach is that the sliding surface has been modified so that the approach has been removed which makes the system more robust and increases its speed of convergence to the reference signal. .

Le personnage chez Edouard Glissant n'est pas un être de papier. Il est multiple et polymorphe, il se construit par pans et se constitue de divers savoirs. Le personnage porte en lui le drame originel de la rupture avec la Matrice lié historiquement à la traite et au transbord. L'intérêt de ce personnage victime d'une non-histoire trouée et rapiécée, est qu'il se constitue sur un chaos. Ce chaos est à l'instar du personnage de nature multiple : temporel, politique, psychologique, sociologique, identitaire, ethnologique. . . Le personnage doit trouver une manière d'exister : la Relation est l'un des concepts mis au point par Edouard Glissant pour définir le mode d'être au monde des sociétés créolisées. L'auteur fractalise son personnage, il le décompose et créolise ainsi le Tout-monde. Edouard Glissant invente un nouveau statut de personnage romanesque, à la fois réaliste et symbolique, opaque, baroque, archipélique et s'inscrivant dans la postmodernité. Ce nouveau type de personnage ouvre sur un imaginaire monde
The character in Edouard Glissant's novel is not a paper being. He is multi-faceted and polymorph, he is built up on patches, he is composed of various pieces of knowledge. The character bears within, the drama of separation from the womb historically linked with the slave trade and the transfert. This character is signifiant in that he is a victim of a pieced-together non-history full of holes, whose entire existence is built on chaos, this chaos is like the character of the multifaceted sort : temporal, political, psychological, sociological, ethnological, with a sense of identify etc. . . In order to surmount this identity crisis, the character must find a way to exist : the relationship is one of the concepts set up by Edouard Glissant to definie the way to be in the world of creole societies. The author split his character up and thus gives a creole identity to the Tout-monde. Edouard Glissant creates a novel character with a new status, simultaneously real and symbolical, opaque, baroque, from an archipelago and comes within the framework of postmodernity. This new sort of character opens the door to an imaginary world

Ce mémoire concerne la stabilisation par modes glissants des systèmes linéaires et non linéaires à retards. Pour ces systèmes dynamiques, l'évolution dépend non seulement des informations à l'instant t mais aussi d'une partie de leur histoire : ils sont dits héréditaires. Dans le premier chapitre, nous rappelons les différentes commandes qui peuvent s'appliquer aux systèmes héréditaires. Leurs avantages ainsi que leurs inconvénients y sont présentés. Dans le second chapitre, nous proposons la construction systématique de lois de commande par modes glissants, qui stabilisent d'une manière robuste les systèmes linéaires à retards sur l'état. Plusieurs cas sont considérés : retard constant, retard inconnu, et retard variant dans le temps. La synthèse de la commande (surface de glissement) est alors faite à l'aide d'outils d'optimisation convexe appelés inégalités linéaires matricielles. Le troisième chapitre étend ces résultats au cas de systèmes non linéaires à retards sur l'état. Plusieurs méthodes y sont proposées suivant que le retard est connu ou non. Enfin, dans le quatrième chapitre, nous étudions le comportement d'un système commandé par modes glissants et soumis à un retard pur sur les entrées ou sur les capteurs de sortie. Nous montrons alors que sous certaines conditions, le système converge dans une bande autour de la surface, dont l'amplitude est évaluée à l'aide d'une fonction de Lyapunov-Razumikhin. Des exemples illustratifs sont présentés tout au long du mémoire.

Étude thermique des contacts glissants est complexe car elle doit associer de nombreux domaines de la mécanique qui sont fortement couplés. Quant aux applications technologiques elles sont nombreuses. Panni elles, le freinage, et notamment le frein à disque, est une des plus importante de part son aspect sécurité. Ils sont soumis à de fortes dégradations telles que fissuration, défonnation structurelle, usure dans lesquelles il est délicat de faire la part des contributions thenniques et tribologiques. Un problème de fond demeure: celui de la connaissance des niveaux de températures atteints, les mécanismes de production d'énergie, etc. La bibliographie regorge d'études sur les contacts glissants qui sont classés en contacts parfaits (ou lisses) et contacts imparfaits (ou avec aspérités). Très peu d'études considèrent le cas d'un contact avec un troisième corps. Ce dernier est généralement négligé sous prétexte de sa faible conductivité. Ces modèles considèrent une génération de chaleur par frottement de type surfacique. De nombreuses études thenniques, analytiques et numériques, appliquées au freinage par disque ont déjà été réalisées. Elles utilisent généralement les hypothèses issues des modèles de contact parfait et plus précisément celle de températures égales au niveau des surfaces apparentes. La comparaison de tous ces modèles sur un freinage d'arrêt automobile a pennis de définir les limites de leur utilisation. Cependant, le niveau des températures atteint ne pennet pas d'expliquer les dégradations subies par les freins à disque. Des observations expérimentales ont montré la présence d'un saut important des températures à l'interface. Ce dernier ne peut être modélisé avec l'hypothèse d'un contact parfait. Un nouveau modèle basé sur la présence d'un troisième corps au sein du contact est proposé. Ce dernier est considéré comme étant volumique, homogène et continu sur toute la surface de contact. Une génération de chaleur volumique unifonne dans tout le troisième corps est dans un premier temps considéré. Les premiers résultats montrent un saut de températures très net entre la surface du disque et celle de la garniture. Une étude de sensibilité a montré une forte dépendance vis-à-vis de l'épaisseur de la couche du troisième corps. Sa conductivité thennique est également un paramètre influant alors que la capacitance thennique ne modifie en rien le niveau des températures. Une seconde étude de sensibilité a été menée sur le profil de génération de chaleur volumique. Trois profils d'accommodation de vitesse ont été considérés. Ils pennettent de montrer une importance vis à vis du gradient de vitesse (représentatif du taux de cisaillement) surtout en ce qui concerne la température de surface de la garniture. Afin de mieux comprendre et d'appréhender le rôle de ce troisième corps d'un point de vue thennique, un dispositif expérimental simple a été élaboré. Il consiste à faire frotter deux cylindres, l'un en saphir (pièce tournante) et l'autre en acier (pièce fixe). Des comparaisons entre les résultats obtenus par des thennocouples de surfaces, une caméra infrarouge ainsi que des observations de surfaces ont permis d'établir des corrélations entre accumulation de troisième corps et échauffement local de la surface de frottement. Un modèle numérique du dispositif a été élaboré sur le principe du contact à trois corps. Les résultats expérimentaux et numériques obtenus sont cohérents et montrent l'intérêt et la représentativité d'un modèle avec troisième corps volumique, homogène et continu.

La formation de polyrotaxanes à base de cyclodextrines a été très largement étudiée au début des années 1990 avec pour but l'obtention de nanotubes de cyclodextrines. L'objectif de ce travail de thèse a été d'utiliser ces structures supramoléculaires pour l'élaboration de nouveaux matériaux polymériques aux propriétés originales : les gels à points de réticulation glissants ou gels glissants. Le principe de base de cette nouvelle gamme de gels, exposé par de Gennes en 1999 est la capacité des nœuds de réticulation à se mouvoir le long de la chaîne porteuse tout en gardant, de manière obligatoire, le contact avec celle-ci. Le système le plus courant afin de synthétiser les polyrotaxanes, précurseurs de ces gels, est le couple polyéthylène-glycol / α-cyclodextrine. La synthèse de ces structures se déroule en deux étapes : i) la formation d'un pseudo-polyrotaxane en milieu aqueux par auto-assemblage entre une chaîne polymère et les macrocycles de cyclodextrines ; ii) la prévention de la désinclusion des macrocycles de la chaîne polymère par " bouchonnage " avec des groupements stériques stoppeurs. Enfin la formation du gel glissant est assurée par la réticulation intermoléculaire en solution des macrocycles inclus le long des chaînes polymères. La caractérisation des gels glissants a alors été conduite dans l'optique d'établir les relations entre la structure interne du gel (degré de complexation des polyrotaxanes, densité de réticulation du réseau) et ces propriétés originales. Leurs comportements diffèrent très sensiblement en fonction du solvant de gonflement et leur dynamique de relaxation a notamment montré un comportement à basses fréquences purement élastique dans le DMSO lié au glissement des macrocycles le long de la chaîne porteuse permis par l'architecture si particulière des points de réticulation
A new class of supramolecular networks, where the crosslink points are not fixed but sliding, has been recently proposed and developed by Okumura and Ito. Their structure is based on intermoleculary crosslinked α-cyclodextrins / poly(ethylene-glycol) precursor polyrotaxanes. The intermolecular crosslinking between the polyrotaxane precursors leads to the formation of a supramolecular sliding network, the sliding gel. These specific networks are synthesized in two main steps: i) the formation of polyrotaxane precursors where the macrocycles are threaded along a template polymer chain; ii) the intermolecular crosslinking of some macrocycles. The sliding gels are expected to have very unusual physical / mechanical properties due to the theoretical ability of the crosslink points to slide along the polymer chain. The aim of this PhD work is to have more insight into the original properties of the sliding gels. For this purpose a controlled synthesis of the topological networks have been carried out and leads to a control of the complexation degree of the polyrotaxanes and of the crosslinking density of the topological network. The characterization of the sliding gels was carried out In order to explain the structure / properties relationships and to highlight on the sliding motion of the crosslink points. In particular the viscoelastic behaviour of the sliding gels in DMSO at low frequencies has revealed all the potential of the sliding crosslink points and underlines the high ability to relax with very low viscous dissipation of this material