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Polymer physics is the field of physics that studies polymers, their fluctuations, mechanical properties, as well as the kinetics of reactions involving degradation and polymerisation of polymers and monomers respectively.〔P. Flory, ''Principles of Polymer Chemistry'', Cornell University Press, 1953. ISBN 0-8014-0134-8.〕〔Pierre Gilles De Gennes, ''Scaling Concepts in Polymer Physics'' CORNELL UNIVERSITY PRESS Ithaca and London, 1979〕〔M. Doi and S. F. Edwards, ''The Theory of Polymer Dynamics'' Oxford University Inc NY, 1986〕〔Michael Rubinstein and Ralph H. Colby, ''Polymer Physics'' Oxford University Press, 2003〕 While it focuses on the perspective of condensed matter physics, polymer physics is originally a branch of statistical physics. Polymer physics and polymer chemistry are also related with the field of polymer science, where this is considered the applicative part of polymers. Polymers are large molecules and thus are very complicated for solving using a deterministic method. Yet, statistical approaches can yield results and are often pertinent, since large polymers (i.e., polymers with a large number of monomers) are describable efficiently in the thermodynamic limit of infinitely many monomers (although the actual size is clearly finite). Thermal fluctuations continuously affect the shape of polymers in liquid solutions, and modeling their effect requires using principles from statistical mechanics and dynamics. As a corollary, temperature strongly affects the physical behavior of polymers in solution, causing phase transitions, melts, and so on. The statistical approach for polymer physics is based on an analogy between a polymer and either a Brownian motion, or other type of a random walk, the self-avoiding walk. The simplest possible polymer model is presented by the ideal chain, corresponding to a simple random walk. Experimental approaches for characterizing polymers are also common, using Polymer characterization methods, such as size exclusion chromatography, Viscometry, Dynamic light scattering, and Automatic Continuous Online Monitoring of Polymerization Reactions (ACOMP)〔US patent 6052184 and US Patent 6653150, other patents pending〕〔F. H. Florenzano; R. Strelitzki; W. F. Reed, “Absolute, Online Monitoring of Polymerization Reactions”, Macromolecules 1998, 31(21), 7226-7238〕 for determining the chemical, physical, and material properties of polymers. These experimental methods also helped the mathematical modeling of polymers and even for a better understanding of the properties of polymers. * Flory is considered the first scientist establishing the field of polymer physics.〔 * French scientists contributed a lot since the 70s (e.g. de Gennes, J. des Cloizeaux). * Doi and Edwards wrote a very famous book in polymer physics.〔 * Russian and Soviet schools of physics (I. M. Lifshitz, A. Yu. Grosberg, A.R. Khokhlov ) have been very active in the development of polymer physics.〔Vladimir Pokrovski, The Mesoscopic Theory of Polymer Dynamics, Springer, 2010〕〔A. Yu. Grosberg, A.R. Khokhlov. Statistical Physics of Macromolecules, 1994, American Institute o Physics〕 ==Models== Models of polymer chains are split into two types: "ideal" models, and "real" models. Ideal chain models assume that there are no interactions between chain monomers. This assumption is valid for certain polymeric systems, where the positive and negative interactions between the monomer effectively cancel out. Ideal chain models provide a good starting point for investigation of more complex systems and are better suited for equations with more parameters. ===Ideal Chains=== * The freely-jointed chain is the simplest model of a polymer. In this model, fixed length polymer segments are linearly connected, and all bond and torsion angles are equiprobable.〔H. Yamakawa, "Helical Wormlike Chains in Polymer Solution", (Springer Verlag, Berlin, 1997)〕 The polymer can therefore be described by a simple random walk and ideal chain. * The freely-rotating chain improves the freely-jointed chain model by taking into account that polymer segments make a fixed bond angle to neighbouring units because of specific chemical bonding. Under this fixed angle, the segments are still free to rotate and all torsion angles are equally likely. * The hindered rotation model assumes that the torsion angle is hindered by a potential energy. This makes the probability of each torsion angle proportional to a Boltzmann factor: :, where is the potential determining the probability of each value of . * In the rotational isomeric state model, the allowed torsion angles are determined by the positions of the minima in the rotational potential energy. Bond lengths and bond angles are constant. * The Worm-like chain is a more complex model. It takes the persistence length into account. Polymers are not completely flexible; bending them requires energy. At the length scale below persistence length, the polymer behaves more or less like a rigid rod. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Polymer physics」の詳細全文を読む スポンサード リンク
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