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Relevant bibliographies by topics / Polymer reptation

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Academic literature on the topic 'Polymer reptation'

Author: Grafiati

Published: 4 June 2021

Last updated: 3 February 2022

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Journal articles on the topic "Polymer reptation"

1

Karatrantos, Argyrios, Russell J. Composto, Karen I. Winey, Martin Kröger, and Nigel Clarke. "Modeling of Entangled Polymer Diffusion in Melts and Nanocomposites: A Review." Polymers 11, no. 5 (May 14, 2019): 876. http://dx.doi.org/10.3390/polym11050876.

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This review concerns modeling studies of the fundamental problem of entangled (reptational) homopolymer diffusion in melts and nanocomposite materials in comparison to experiments. In polymer melts, the developed united atom and multibead spring models predict an exponent of the molecular weight dependence to the polymer diffusion very similar to experiments and the tube reptation model. There are rather unexplored parameters that can influence polymer diffusion such as polymer semiflexibility or polydispersity, leading to a different exponent. Models with soft potentials or slip-springs can estimate accurately the tube model predictions in polymer melts enabling us to reach larger length scales and simulate well entangled polymers. However, in polymer nanocomposites, reptational polymer diffusion is more complicated due to nanoparticle fillers size, loading, geometry and polymer-nanoparticle interactions.

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Cloizeaux, J. des. "Double Reptation vs. Simple Reptation in Polymer Melts." Europhysics Letters (EPL) 5, no. 5 (March 1, 1988): 437–42. http://dx.doi.org/10.1209/0295-5075/5/5/010.

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Cloizeaux, J. des. "Double Reptation vs. Simple Reptation in Polymer Melts." Europhysics Letters (EPL) 6, no. 5 (July 1, 1988): 475. http://dx.doi.org/10.1209/0295-5075/6/5/018.

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Composto, Russell J., Edward J. Kramer, and Dwain M. White. "Reptation in polymer blends." Polymer 31, no. 12 (December 1990): 2320–28. http://dx.doi.org/10.1016/0032-3861(90)90319-t.

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SKOLNICK, JEFFREY, ROBERT YARIS, and ANDRZEJ KOLINSKI. "PHENOMENOLOGICAL THEORY OF POLYMER MELT DYNAMICS." International Journal of Modern Physics B 03, no. 01 (January 1989): 33–64. http://dx.doi.org/10.1142/s0217979289000038.

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A particularly interesting problem in polymer physics is the mechanism by which an individual polymer chain moves in a polymer melt or concentrated polymer solution. The first rather successful model of polymer dynamics was the reptation model of de Gennes which asserts that due to the effect of entanglements a polymer finds itself confined to a tube. Thus, the dominant long wavelength motion of the chain should be slithering out the ends of the tube. In order to examine the validity of the reptation model, a series of dynamic Monte Carlo simulations were performed. Although the simulations are on chains sufficiently long that agreement with the experimentally observed scaling with degree of polymerization n of the self diffusion constant and terminal relaxation time is observed, reptation does not appear to be the dominant mechanism of long distance motion. Rather the motion is isotropic, with the slowdown from dilute solution behavior arising from the formation of dynamic entanglements — rare long lived contacts where a given chain drags another chain through the melt for times on the order of longest internal relaxation time. Motivated by the simulations results, a phenomenological theory for the diffusive and viscoelastic behavior is developed that is consistent with both simulations and experiment and which does not invoke reptation. The major conclusions arising from the theoretical approach are described, and comparison is made with experiment.

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Maestro, Armando, Hani M. Hilles, Francisco Ortega, Ramón G. Rubio, Dominique Langevin, and Francisco Monroy. "Reptation in langmuir polymer monolayers." Soft Matter 6, no. 18 (2010): 4407. http://dx.doi.org/10.1039/c0sm00250j.

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Schiessel, H., J. Widom, R. F. Bruinsma, and W. M. Gelbart. "Polymer Reptation and Nucleosome Repositioning." Physical Review Letters 86, no. 19 (May 7, 2001): 4414–17. http://dx.doi.org/10.1103/physrevlett.86.4414.

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Sackmann, Erich, Josef Käs, and Helmut Strey. "The observation of polymer reptation." Advanced Materials 6, no. 6 (June 1994): 507–9. http://dx.doi.org/10.1002/adma.19940060617.

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Schaefer, D. W. "Polymer reptation in semidilute solution." Journal of Polymer Science: Polymer Symposia 73, no. 1 (March 8, 2007): 121–31. http://dx.doi.org/10.1002/polc.5070730117.

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Scher, Harvey, and Michael F. Shlesinger. "On reptation in polymer melts." Journal of Chemical Physics 84, no. 10 (May 15, 1986): 5922–24. http://dx.doi.org/10.1063/1.449905.

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Dissertations / Theses on the topic "Polymer reptation"

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Lang, Philipp Sebastian [Verfasser], and Erwin [Akademischer Betreuer] Frey. "Reptation in entangled polymer networks : a simulational study of the significance of constraint release for reptation / Philipp Sebastian Lang. Betreuer: Erwin Frey." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2015. http://d-nb.info/1104698013/34.

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Richardson, M. J. E. "Two-species non-equilibrium processes in one dimension." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362106.

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Hou, Jixuan. "Stress relaxation in entangled polymer melts." Thesis, Lyon, École normale supérieure, 2012. http://www.theses.fr/2012ENSL0733.

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La relation entre les propriétés viscoélastiques complexes de liquides polymères et leur structure microscopique et la dynamique est une question clé dans la science des matériaux et de la biophysique. Les théories modernes de la dynamique des polymères et la rhéologie décrivent les aspects universels du comportement viscoélastique sur la base de l'idée que les enchevêtrements moléculaires confinent filaments individuels à une dimension, la dynamique diffusifs (reptation) dans le tube-comme les régions dans l'espace. Alors que le modèle de tube est validé par son succès, ses éléments constitutifs (les statistiques et la dynamique de l'axe du tube ou des chemins primitifs et de l'confinement "cage" de chaînes voisines) ne sont pas directement observables. (1) Nous présentons un vaste ensemble de résultats de simulation pour la relaxation des contraintes à l'équilibre et l'étape-tendues perles printemps polymères fondus (En collaboration avec: C. Svaneborg et GS Grest). Les données nous permettent d'explorer la dynamique de la chaîne et le module de la relaxation de cisaillement dans le régime plateau pour les chaînes avec Z~40 enchevêtrements et dans le régime de relaxation terminale pour Z~10. Nous avons effectué des tests sans paramètres de plusieurs modèles différents de tubes à l'aide de (Rouse) la mobilité connue des chaînes unentangled et la longueur d'enchevêtrement de fusion déterminé par l'analyse du chemin primitif de l'état microscopique topologique de nos systèmes. (2) Nous présentons une compréhension complète pour la détente des empêtré polymère linéaire fond que les liens de la dynamique et la théorie de Rouse tube par une interprétation dynamique qui s’appellel’analyse du chemin primitive. La chaîne primitive, qui est la moyenne d'ensemble des conformations de la chaîne, se rétrécit strictement d’après la dynamique Rouse jusqu'à ce qu'il renconte les obstacles formés par d'autres chaînes primitives. Le temps d'arrêt de la diminution peut être déterminée par l'argument que la zone balayée par la chaîne primitive sur une longueur de propagation de tension qui est égale à la taille du maille de filet du travail formé par les chaînes de primitives. Le processus physique avant l'heure d'arrêt est assez présenté par l'analyse du chemin primitif. Après le temps d'arrêt, les longueurs primitives seront rétrécites par la reptation et la fluctuation de la longueur de contour .Cette procedure peut être décrite comme la modèle du tube, par exemple, Likhtman-McLeish (LM) la théorie. (3) Nous constatons que la théorie sous-estime la relaxation LM module de cisaillement dû à un double comptage de l'effet de courte longueur d'onde (p> Z) dans les modes partie de relaxation de Rouse et en fonction de la trompe de mémoire μ (t). LM extrapolé μ (t) à la limite du continuum, ce qui entraîne une décroissance sur des échelles de temps inférieur au temps de l'intrication, où le mouvement de la chaîne primitive devrait être négligeable. Pour corriger cela, nous avons retiré de la partie de fluctuation contour longueur de μ (t) la contribution des modes avec un temps de relaxation plus court que le temps d'enchevêtrement. Nous trouvons un excellent accord entre nos données de simulation et la théorie LM modifiée en utilisant l'approximation reptation double pour la libération de contrainte, ce qui démonte que l'analyse du chemin primitif de la structure microscopique apporte du modèle de tube avec une puissance prédictive des processus dynamiques. L'utilisation de systèmes plus complexes pour le traitement de la libération de contrainte devrait conduire à un accord encore mieux
The relation between the complex viscoelastic properties of polymer liquids and their microscopic structure and dynamics is a key issue in materials science and biophysics. Modern theories of polymer dynamics and rheology describe the universal aspects of the viscoelastic behavior based on the idea that molecular entanglements confine individual filaments to a one-dimensional, diffusive dynamics (reptation) in tube-like regions in space. While the tube model is validated through its success, its constituting elements (the statistics and dynamics of the tube axis or primitive paths and of the confining "cage" of neighboring chains) are not directly observable. (1) We present an extensive set of simulation results for the stress relaxation in equilibrium and step-strained bead-spring polymer melts (In cooperation with: C. Svaneborg and G. S. Grest). The data allow us to explore the chain dynamics and the shear relaxation modulus into the plateau regime for chains with Z~40 entanglements and into the terminal relaxation regime for Z~10. We have performed parameter-free tests of several different tube models by using the known (Rouse) mobility of unentangled chains and the melt entanglement length determined via the primitive path analysis of the microscopic topological state of our systems. (2) We present a full understanding for relaxation of entangled linear polymer melts that links the Rouse dynamics and tube theory via a dynamic interpretation of the so called primitive path analysis. The primitive chain, which is the ensemble average of the chain conformations, shrinks strictly following the Rouse dynamic until it encounters the obstacles formed by other primitive chains. The stop time of the shrinking can be determined by the argument that the area swept by the primitive chain over a tension propagation length is equal to the mesh size of the net work formed by the primitive chains. The physical process before the stop time is fairly presented by primitive path analysis. After the stop time, the primitive length shrinks via reptation and contour length fluctuation, which is well described by the tube theory, e.g. Likhtman-McLeish (LM) theory. (3) We find that the LM theory underestimates the shear relaxation modulus due to a double-counting of the effect of short-wavelength (p>Z) modes in Rouse relaxation part and in tube memory function μ(t). LM extrapolated μ(t) to the continuum limit, resulting a decay on time scales smaller than the entanglement time, where the motion of the primitive chain should be negligible. To correct this, we have removed from the contour length fluctuation part of μ(t) the contribution of modes with a relaxation time shorter than entanglement time. We find excellent agreement between our simulation data and the modified LM theory using the double reptation approximation for constraint release, which demonstrates that the primitive path analysis of the microscopic structure endows the tube model with predictive power for dynamical processes. The use of more elaborate schemes for treating constraint release should lead to even better agreement

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Herrmann, Axel [Verfasser], and Ernst [Akademischer Betreuer] RößLer. "Polymer Melts Investigated by Field Cycling NMR Relaxometry: From Simple Liquid to Reptation Dynamics / Axel Herrmann. Betreuer: Ernst Rößler." Bayreuth : Universität Bayreuth, 2012. http://d-nb.info/1059412667/34.

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Lin, Heng. "CROSSOVER FROM UNENTANGLED TO ENTANGLED DYNAMICS: MONTE CARLO SIMULATION OF POLYETHYLENE, SUPPORTED BY NMR EXPERIMENTS." Akron, OH : University of Akron, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1142028839.

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Dissertation (Ph. D.)--University of Akron, Dept. of Polymer Science, 2006.
"May, 2006." Title from electronic dissertation title page (viewed 10/11/2006) Advisor, Wayne L. Mattice; Committee members, Ernst D. von Meerwall, Ali Dhinojwala, Gustavo A. Carri, Richard J. Elliott; Department Chair, Mark D. Foster; Dean of the College, Frank N. Kelley; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

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Huang, Zhenyu. "Crystallization and Melting Behavior of Linear Polyethylene and Ethylene/Styrene Copolymers and Chain Length Dependence of Spherulitic Growth Rate for Poly(Ethylene Oxide) Fractions." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/29211.

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The crystallization and melting behavior of linear polyethylene and of a series of random ethylene/styrene copolymers was investigated using a combination of classical and temperature modulated differential scanning calorimetry. In the case of linear polyethylene and low styrene content copolymers, the temporal evolutions of the melting temperature, degree of crystallinity, and excess heat capacity were studied during crystallization. The following correlations were established: 1) the evolution of the melting temperature with time parallels that of the degree of crystallinity, 2) the excess heat capacity increases linearly with the degree of crystallinity during primary crystallization, reaches a maximum during the mixed stage and decays during secondary crystallization, 3) the rates of shift of the melting temperature and decay of the excess heat capacity lead to apparent activation energies that are very similar to these reported for the crystal ac relaxation by other techniques. Strong correlations in the time domain between the secondary crystallization and the evolution of the excess heat capacity suggest that the reversible crystallization/melting phenomenon is associated with molecular events in the melt-crystal fold interfacial region. In the case of higher styrene content copolymers, the multiple melting behavior at high temperature is investigated through studies of the overall crystallization kinetics, heating rate effects and partial melting. Low melting crystals can be classified into two categories according to their melting behavior, superheating and reorganization characteristics. Low styrene content copolymers still exhibit some chain folded lamellar structure. The shift of the low melting temperature with time in this case is tentatively explained in terms of reorganization effects. Decreasing the crystallization temperature or increasing the styrene content leads to low melting crystals more akin to fringed-micelles. These crystals exhibit a lower tendency to reorganize during heating. The shift of their melting temperature with time is attributed to a decrease in the conformational entropy of the amorphous fraction as a result of constraints imposed by primary and secondary crystals. To further understand the mechanism of formation of low melting crystals, quasi-isothermal crystallization experiments were carried out using temperature modulation. The evolution of the excess heat capacity was correlated with that of the melting behavior. On the basis of these results, it is speculated that the generation of excess heat capacity at high temperature results from reversible segmental exchange on the fold surface. On the other hand, the temporal evolution of the excess heat capacity at low temperature for high styrene content copolymers is attributed to the reversible segment attachment and detachment on the lateral surface of primary crystals. The existence of different mechanisms for the generation of excess heat capacity in different temperature ranges is consistent with the observation of two temperature regimes for the degree of reversibility inferred from quasi-isothermal melting experiments. In a second project, the chain length and temperature dependences of spherulitic growth rates were studied for a series of narrow fractions of poly(ethylene oxide) with molecular weight ranging from 11 to 917 kg/mol. The crystal growth rate data spanning crystallization temperatures in regimes I and II was analyzed using the formalism of the Lauritzen-Hoffman (LH) theory. Our results are found to be in conflict with predictions from LH theory. The Kg ratio increases with molecular weight instead of remaining constant. The chain length dependence of the exponential prefactor, G0, does not follow the power law predicted by Hoffman and Miller (HM). On this basis, the simple reptation argument proposed in the HM treatment and the nucleation regime concept advanced by the LH model are questioned. We proposed that the observed I/II regime transition in growth rate data may be related to a transition in the friction coefficient, as postulated by the Brochard-de Gennnes slippage model. This mechanism is also consistent with recent calculations published by Toda in which both the rates of surface nucleation and substrate completion processes exhibit a strong temperature dependence.
Ph. D.

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Nam, Gi-moon. "Dynamics of confined biofilaments." Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAE048/document.

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Cette thèse est consacrée à la mécanique et à la mécanique statistique de biofilaments/biopolymères et de leur modèle le plus répandu le Worm-Like Chain (WLC) qu’il s’avère nécessaire d’étendre. Nous étudions WLC à 2-d en présence d’obstacles plus proches que la longueur de persistance. Nous caractérisons le mouvement aux temps courts par des simulations numériques complétées par des calculs analytiques. Des concepts similaires servent à décrire des ADN greffés balayés par le front d’une vésicule en cours d’étalement, l’adhésion de la vésicule est promue par des paires biotine/streptavidine qui contraignent les molécules d'ADN sur des chemins étroits où ils peuvent être imagés. Les microtubules (MT) ici stabilisés au taxol, présentent par contre certains comportements qui échappent au WLC et doivent être ramenés à leur structure interne : i)les déflexions latérales d’un MT attaché par un bout correspondent à une longueur de persistance apparente qui augmente avec la longueur ii) les MT adoptent des formes super-hélicoïdales. Ces deux points sont établis au moyen d’analyses de forme des MT. Des transitions de forme corrélées le long du MT mises en évidence sont compatibles avec un modèle basé sur la bistabilité du dimère de tubuline. Finalement un modèle de chaîne super-hélicoïdale comprenant une courbure et une torsion spontanées élargi le WLC. Confiné à 2-d, HWLC peut adopter un état fondamental circulaire ou sinueux caractérisé par le nombre de points d’inflexion où se concentre la torsion (twist-kink). Dans le cas circulaire, il existe des états métastables proches, à petit nombre de twist-kinks, hyperflexibles
This PhD is devoted to the mechanics and statistical mechanics of biofilaments and their most widespread model, the Worm-Like Chain (WLC) model, which, as it turns out, needs to be extended. We study the WLC in 2-d in the presence of obstacles closer than their persistence length. We characterize the short time motion by numerical simulations complemented by analytical calculations. Similar concepts serve to describe grafted DNAs swept by the front of a spreading vesicle whose adhesion is promoted by biotin/streptavidin bonds, which constrain the DNAs on narrow paths where they can be imaged. Microtubules (MT), here stabilized by taxol, show features which cannot be rationalized by the WLC and shall be related to their internal structure : i)lateral deflections of a clamped MT correspond to an effective persistence length growing with the MT size ii) MT adopt super-helical shapes. These two points are proven by refined image analysis. We analyze shape transitions correlated along the MT which are compatible with a model based on dimer bi-stability. Finally, a super helical chain model (HWLC) allowing for spontaneous curvature and twist is developed which extends the WLC. When confined to 2-d, the HWLC can adopt a ground state which is circular or wavy with inflection points where twist accumulates, so-called twist-kinks. In the circular case there exist close metastable states, with a small number of twist-kinks, which are hyperflexible

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Hubert, Sylvain. "Theoretical study of polymers: Flow-induced deformation in nanochannels and reptation dynamics in heterogeneous gels." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/29115.

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In 1992, B. Smith, L. Finzi and C. Bustamante were the first to directly observe the behaviour of a single DNA molecule with the help of video fluorescence microscopy. Their results greatly improved our understanding of the static and dynamic properties of a single isolated chain which represents the foundation of polymer physics. A series of experimental results and theoretical models followed the work of Smith et al. Current theoretical approaches to study polymers involve many techniques: thermodynamic analysis, field theory, scaling, renormalization group theory and computer simulations. In Chapter 2, we present a Molecular Dynamics study of the effect of strong lateral confinement on the properties of a tethered polymer pulled at constant velocity. Our results are compared with recent theoretical predictions and experimental results. One can also ask questions about the behaviour of dilute polymer solutions, or even concentrated solutions such as melts or gels, where the interactions among the polymers are important. For instance, gel electrophoresis (GE) is one of the most common analytical tools used in biology. Since the introduction of GE in 1937, molecular biology has grown substantially. Indeed, GE has shown to be an excellent separation method for DNA molecules since in free solution, the electrophoretic mobility of a DNA molecule is independent of its size. Because of that, most of the theoretical developments in the field have been aimed at improving DNA electrophoretic separation tools. In 1993, Zimm and Lumpkin proposed a new reptation model to explain gel electrophoresis of polyelectrolytes in irregular matrices. Following this work, we propose in Chapter 3 a more detailed model of this problem where the well-known memory effects of the standard reptation theory are taken into account. Our results are in qualitative agreement with available experimental results and disagree with those of Zimm and Lumpkin. In Chapter 4, we examine the reptation of a polymer in a static environment with quenched random energies that are correlated over a finite length scale lambda based on the algorithm detailed in Chapter 3. The results obtained differ from our previous model (Chapter 3) and are compared with those of Zimm and Lumpkin.

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Nam, Gi-Moon. "Dynamics of confined biofilaments." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00976029.

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This PhD is devoted to the mechanics and statistical mechanics of biofilaments and their most widespread model, the Worm-Like Chain (WLC) model, which, as it turns out, needs to be extended. We study the WLC in 2-d in the presence of obstacles closer than their persistence length. We characterize the short time motion by numerical simulations complemented by analytical calculations. Similar concepts serve to describe grafted DNAs swept by the front of a spreading vesicle whose adhesion is promoted by biotin/streptavidin bonds, which constrain the DNAs on narrow paths where they can be imaged. Microtubules (MT), here stabilized by taxol, show features which cannot be rationalized by the WLC and shall be related to their internal structure : i)lateral deflections of a clamped MT correspond to an effective persistence length growing with the MT size ii) MT adopt super-helical shapes. These two points are proven by refined image analysis. We analyze shape transitions correlated along the MT which are compatible with a model based on dimer bi-stability. Finally, a super helical chain model (HWLC) allowing for spontaneous curvature and twist is developed which extends the WLC. When confined to 2-d, the HWLC can adopt a ground state which is circular or wavy with inflection points where twist accumulates, so-called twist-kinks. In the circular case there exist close metastable states, with a small number of twist-kinks, which are hyperflexible.

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Campise, Florencia. "Influencia de los defectos, entrelazamientos y parámetros estructurales en las propiedades viscolásticas poliméricas modelo." Doctoral thesis, 2017. http://hdl.handle.net/11086/5844.

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La estructura de redes poliméricas está caracterizada por la densidad de puntos de entrecruzamiento, la fracción en volumen del material elásticamente activo, los defectos topológicos, y los efectos de entrelazamiento. La estructura y la respuesta viscoelástica de redes poliméricas entrecruzadas son altamente sensibles a la presencia de defectos estructurales. Estas no idealidades reducen la densidad de entrecruzamientos, y con ello reducen la respuesta elástica, incrementan el hinchamiento por solvente y controlan la dinámica disipativa de los elastómeros. En esta tesis, se estudió la relación entre la estructura de redes modelo de polidimetilsiloxano y sus propiedades macroscópicas a partir de experimentos de Resonancia Magnética Nuclear (RMN). Modelos de Campo Medio basados en la estructura de las redes, el modelo del tubo y el modelo phantom fueron utilizados para analizar los resultados en términos del contenido de defectos y entrelazamientos, así como también de otros parámetros estructurales.

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Book chapters on the topic "Polymer reptation"

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Jongschaap, Robert J. J., and Bernard J. Geurts. "A New Reptation Model for Polymeric Liquids." In Integration of Fundamental Polymer Science and Technology—2, 461–65. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-1361-5_69.

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Ibar, Jean Pierre. "Shear-Thinning of Polymeric Melts: The Failure of the Reptation Model." In The Physics of Polymer Interactions, 403–15. München: Carl Hanser Verlag GmbH & Co. KG, 2019. http://dx.doi.org/10.3139/9781569907115.007.

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Rahmoun, Somia, Fabrice Mairesse, Hiroshi Uji-i, Johan Hofkens, and Tadeusz Sliwa. "Curve Extraction by Geodesics Fusion: Application to Polymer Reptation Analysis." In Lecture Notes in Computer Science, 79–88. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-33618-3_9.

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Kabanemi, Kalonji K., and Jean-François Hétu. "Reptation Model for the Dynamics and Rheology of Particle Reinforced Polymer Chains." In Modeling and Prediction of Polymer Nanocomposite Properties, 63–94. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527644346.ch4.

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Léger, L., H. Hervet, M. F. Marmonier, and J. L. Viovy. "Dynamics of Entangled Polymers: Reptation." In New Trends in Physics and Physucal Chemistry of Polymers, 397–417. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4613-0543-9_33.

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Léger, L. "Dynamic Properties of Entangled Polymers: The Reptation Model." In Structure and Dynamics of Molecular Systems, 179–94. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4662-0_9.

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Öttinger, Hans Christian. "Reptation Models for Concentrated Solutions and Melts." In Stochastic Processes in Polymeric Fluids, 257–91. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-58290-5_6.

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Slater, Gary W., and Jaan Noolandi. "The Biased Reptation Model of DNA Gel Electrophoresis." In New Trends in Physics and Physucal Chemistry of Polymers, 547–600. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4613-0543-9_41.

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Atanassov, A. M. "QUANTUM INTERPRETATION OF THE SECONDARY NUCLEATION RATE AND THE REPTATION RATE THEORY - A COMPARATIVE STUDY." In Morphology of Polymers, edited by Blahoslav Sedláček, 225–34. Berlin, Boston: De Gruyter, 1986. http://dx.doi.org/10.1515/9783110858150-016.

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Tejedor, Andrés R., and Jorge Ramírez. "Effect of a Constant Drift in the Reptation Dynamics of Entangled Polymers." In Springer Proceedings in Materials, 159–62. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-27701-7_33.

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Conference papers on the topic "Polymer reptation"

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RICHTER, D. "FROM ENTROPY DRIVEN MOTION TO REPTATION — LARGE SCALE DYNAMICS IN POLYMER MELTS." In Proceedings of the Sixth Summer School of Neutron Scattering. WORLD SCIENTIFIC, 1998. http://dx.doi.org/10.1142/9789814447270_0014.

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Feigl, Kathleen, and Deepthika C. Senaratne. "Calculation of Polymer Flow Using Micro-Macro Simulations." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61575.

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A micro-macro simulation algorithm for the calculation of polymeric flow is developed and implemented. The algorithm couples standard finite element techniques to compute velocity and pressure fields with stochastic simulation techniques to compute polymer stress from simulated polymer dynamics. The polymer stress is computed using a microscopic-based rheological model which combines aspects of network and reptation theory with aspects of continuum mechanics. The model dynamics include two Gaussian stochastic processes each of which is destroyed and regenerated according to a survival time randomly generated from the material’s relaxation spectrum. The Eulerian form of the evolution equations for the polymer configurations are spatially discretized using the discontinuous Galerkin method. The algorithm is tested on benchmark contraction domains for a polyisobutylene (PIB) solution. In particular, the flow in the abrupt die entry domain is simulated and the simulation results are compared with experimental data. The results exhibit the correct qualitative behavior of the polymer and agree well with the experimental data.

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Mayeed, Mohammed S., and Takahisa Kato. "Replenishment of Ultrathin Liquid Perfluoropolyether Z Films on Solid Surfaces." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62829.

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Applying the reptation algorithm to a simplified perfluoropolyether Z off-lattice polymer model an NVT Monte Carlo simulation has been performed. Bulk condition has been simulated first to compare the average radius of gyration with the bulk experimental results. Then the model is tested for its ability to describe dynamics. After this, it is applied to observe the replenishment of ultrathin (4 nm thickness) liquid films on solid flat carbon surfaces. The replenishment rate for trenches of different widths (8, 12 and 16 nm for molecular weight of 3840 g/mol and 12 nm for molecular weights of 2500 and 1700 g/mol) between two films of perfluoropolyether Z from the Monte Carlo simulation are compared to those obtained solving the diffusion equation using the experimental diffusion coefficients of Ma et al. with room condition in both the cases. Replenishment per Monte Carlo cycle seems to be a constant multiple of replenishment per second at least up to 2 nm replenished film thickness of the trenches over the carbon surface. Considerable good agreement has been achieved here between the experimental results and the dynamics of molecules using reptation moves in the ultrathin liquid films on solid surfaces.

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Refaa, Zakariaa, Mhamed Boutaous, Shihe Xin, and Patrick Bourgin. "Towards the Enhancement of the Crystallization Kinetics of a Bio-Sourced and Biodegradable Polymer PLA (Poly (Lactic Acid))." In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21952.

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PLA (Poly Lactic Acid) is a bio-sourced and a biodegradable polymer. It represents an interesting substitute for some petrochemical based polymers, especially because of its wide range of applications in the biomedical, agriculture and packaging fields. Unfortunately, PLA exhibits slow crystallization kinetics, limiting the amount of crystallinity in the final product, which is a handicap in order to extend its use. Many authors have investigated the crystallization of polymers; nevertheless several physical mechanisms remain not yet understood. This work aims a complete characterization of PLA in order to improve the understanding of its crystallization kinetics. The quiescent crystallization was investigated using Differential Scanning Calorimetry (DSC) measurements in isothermal and non-isothermal conditions for PLA and PLA with 5wt % talc. The flow effect on crystallization was studied using a thermocontrolled hot-stage shearing device (Linkam) coupled with an optical microscope. The number of activated nuclei and the growth rate were measured as functions of temperature. In addition, the linear viscoelastic properties were obtained from a rheometer with plate-plate geometry. The enhancement of the crystallization was quantified and analyzed in terms of the half crystallization time t1/2. This characteristic time t1/2 is found to be drastically decreased by both the talc and the flow which promote supplementary nucleation leading to various crystalline microstructures. The flow is known to orient and stretch molecules leading to an extra nucleation. An original description of this phenomenon is proposed using two characteristic Weissenberg numbers; based on the definition of Rousse and reptation times. Finally, we have proposed a semi-empirical model to quantify the thermal and flow contributions on the crystallization.

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Reports on the topic "Polymer reptation"

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Banks, H. T., Negash G. Medhin, and Gabriella A. Pinter. Nonlinear Reptation in Molecular Based Hysteresis Models for Polymers. Fort Belvoir, VA: Defense Technical Information Center, December 2003. http://dx.doi.org/10.21236/ada446720.

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