Award Date

1-1-1989

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Physics

First Committee Member

J. C. Selser

Number of Pages

113

Abstract

A study of the internal behavior of polystyrene in toluene and cyclohexane was done using photon correlation spectroscopy. In the experiments laser light of two different wavelengths was scattered from local concentration fluctuations in the polymer and autocorrelation function was calculated; The autocorrelation function can be written as a sum of decaying exponentials. The center-of-mass mode with a decay constant Dq{dollar}\sp2{dollar} is contained in every mode. D is the polymer diffusion coefficient and can be measured in low angle light scattering experiments and q is the magnitude of the scattering vector. Thus this center-of-mass mode can be factored out of the correlation function and a new function H(t) can be calculated. The experimental function was fit by a multiexponential fit routine to extract the value for the averaged internal mode; The quantity 2/{dollar}\tau\sb1{dollar} showed a concentration dependence in good solvent that has not been reported before. (Abstract shortened with permission of author.).

Keywords

Average; Conce; Concentration; Correlation; Dependence; First; Internal; Measurement; Mode; Photon; Polystyrene; Scattering; Solution; Spectroscopy; Vector

Controlled Subject

Polymers; Polymerization; Chemistry; Optics

File Format

pdf

File Size

3338.24 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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