Journal ArticleDOI
A Theory of the Linear Viscoelastic Properties of Dilute Solutions of Coiling Polymers
TLDR
In this paper, the necessary coordination of the motions of different parts of a polymer molecule is made the basis of a theory of the linear viscoelastic properties of dilute solutions of coiling polymers.Abstract:
The necessary coordination of the motions of different parts of a polymer molecule is made the basis of a theory of the linear viscoelastic properties of dilute solutions of coiling polymers. This is accomplished by use of the concept of the submolecule, a portion of polymer chain long enough for the separation of its ends to approximate a Gaussian probability distribution. The configuration of a submolecule is specified in terms of the vector which corresponds to its end‐to‐end separation. The configuration of a molecule which contains N submolecules is described by the corresponding set of N vectors. The action of a velocity gradient disturbs the distribution of configurations of the polymer molecules away from its equilibrium form, storing free energy in the system. The coordinated thermal motions of the segments cause the configurations to drift toward their equilibrium distribution. The coordination is taken into account by the mathematical requirement that motions of the atom which joins two submolecules change the configurations of both submolecules. By means of an orthogonal transformation of coordinates, the coordination of all the motions of the parts of a molecule is resolved into a series of modes. Each mode has a characteristic relaxation time. The theory produces equations by means of which the relaxation times, the components of the complex viscosity, and the components of the complex rigidity can be calculated from the steady flowviscosities of the solution and the solvent, the molecular weight and concentration of the polymer, and the absolute temperature. Limitations of the theory may arise from the exclusion from consideration of (1) very rapid relaxation processes involving segments shorter than the submolecule and (2) the obstruction of the motion of a segment by other segments with which it happens to be in contact. Another possible cause of disagreement between the theory and experimental data is the polydispersity of any actual polymer; this factor is important because the calculated relaxation times increase rapidly with increasing molecular weight.read more
Citations
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Journal ArticleDOI
The effect of entanglements in rubber elasticity
Sam F. Edwards,T. A. Vilgis +1 more
TL;DR: A theory of rubber elasticity based on the concept of entanglements was presented in this paper, where it was shown that for small deformation the molecular mechanism of stretching is dominated by the slippage of chains.
Journal ArticleDOI
Molecular morphology in semicrystalline polymers
Paul J. Flory,Do Y. Yoon +1 more
TL;DR: The topology of the copiously interspersed chains in the liquid state must be largely conserved during the process of crystallisation, preexisting entanglements being concentrated in the non-crystalline regions as discussed by the authors.
Book
NMR Studies of Translational Motion
TL;DR: A detailed discussion of magnetic field gradient methods applied to Magnetic Resonance Imaging (MRI) is included, alongside extensive referencing throughout, providing a timely, definitive book to the subject, ideal for researchers in the fields of physics, chemistry and biology.
Journal ArticleDOI
Structure and linear viscoelasticity of flexible polymer solutions: comparison of polyelectrolyte and neutral polymer solutions
TL;DR: The current state of understanding for solution conformations of flexible polymers and their linear viscoelastic response is reviewed in this paper, where correlation length, tube diameter, and chain size of neutral polymers in good solvent and polyelectrolyte solutions with no added salt are compared.
Journal ArticleDOI
Theory of twisting and bending of chain macromolecules; analysis of the fluorescence depolarization of DNA
Mary D. Barkley,Bruno H. Zimm +1 more
TL;DR: In this article, an elastic model of semiflexible chain macromolecules is developed in order to treat internal rotatory Brownian motion in the DNA helix, and dynamical equations for torsion and bending of the chain are generated, using results from classical elasticity and hydrodynamic theories.
References
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Journal ArticleDOI
Piezoelectric Crystals and Their Applications to Ultrasonics
Warren P. Mason,Hans Baerwald +1 more
TL;DR: Piezoelectric crystals and their application to ultrasonics were discussed in this paper, where the authors proposed a method for the extraction of the ultrasonic properties of these crystals.