Dynamics of Molecular Crystals, Polymers, and Adsorbed Species

White, John W.

doi:10.1007/978-3-642-81113-5_4

Cited by 7 publications

(1 citation statement)

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“…This is an important method for the study of crystal dynamics. It has been applied to polymers (3,16) and interesting results have been obtained. Difficulties arise from the lack of macroscopic single crystals and from the requirement to use deuterated polymers because of the low coherent cross section of hydrogen (1.8·1o-24 cm 2 ).…”

Section: ) Low Frequency Vibrations Of An N-alkane As a Model Of Polmentioning

confidence: 94%

Studies of structure and dynamics of solid polymers by elastic and inelastic neutron scattering

Fischer¹

1978

Pure and Applied Chemistry

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(The measurements were carried out partly at the Institute Laue Langevin, Grenoble, and partly at the Kernforschungsanlage Jülich).Abstract -Neutron scattering methods can be applied to solid polymers in order to investigate the structure of the bulkmaterial as well as the nature of the molecular motion. A review of some recently performed studies is presented. Diffusional motion in crystals of chain molecules has been studied by means of quasielastic scattering for the case of n-C 33 H68 as an example for the relationship between structure and molecular motion. It can be shown that below the so-called rotational transition the paraffin crystals exhibit two types of molecular motion: a translational jump (•t = 0.5 10-8 s) and a 180°-rotational jump _8 (•r = 2.5 10 s). The low frequency vibrations in n-alkanes as models of polyethylene have been investigated by means of inelastic incoherent scattering. The longitudinal acoustical mode as well as other lattice vibrations are observed with frequencies, which are in good agreement with the calculations by Kitagawa and Miyazawa. As examples for structure studies the results of neutron scattering of cellulose fibres "stained" by deuterium and of semicrystalline statistical copolymers are mentioned. Further the problern of chain configuration in crystalline polymers is discussed to some extent. It is shown that the preliminary results obtained in various laboratories do not allow a uniform conclusion, but there is overwhelming evidence that in the case of crystallization from the melt the observed scattering curves are inconsistent with the model of adjacent re-entry and regular folds.

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Section: ) Low Frequency Vibrations Of An N-alkane As a Model Of Polmentioning

confidence: 94%

Studies of structure and dynamics of solid polymers by elastic and inelastic neutron scattering

Fischer¹

1978

Pure and Applied Chemistry

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Scattering

Gabrys

Tomlins

2012

Encyclopedia of Polymer Science and Technology

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Scattering experiments on polymer systems can provide not only important structural information, but also their dynamics. In this article we overview the theoretical and practical aspects of scattering applied for elastic/inelastic and coherent/incoherent cases. Details about X‐ray, neutron and light scattering instrumentation, (such as diffractometers for elastic scattering and spectrometers for inelastic scattering), sample geometry, correlation functions, and data treatment are presented. We conclude with examples showing representative scattering techniques used to characterize polymers conformation, phase size, and chain motion.

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