Determination of Molecular-Weight Distribution of Water-Soluble Macromolecules by Dynamic Light Scattering

Document Type

Article

Publication Date

1991

Department

Polymers and High Performance Materials

Abstract

An algorithm for the extraction of molecular weight distributions of typical high molecular weight, water-soluble polymers from dynamic light scattering has been developed. A function fit method was used to determine the best distribution parameters of a generalized exponential function. The algorithm employs a Marquardt-Levenburg constrained nonlinear least squares regression. A series approximation of the integral equation which is generated was attempted. This approach was abandoned because of difficulties with series convergence. A modified Rhomberg numerical integration was utilized with limited success. Two water-soluble polymer molecular weight distributions were obtained. The distributions of a polyethyleneoxide and a polyacrylamide were determined and compared with distributions obtained using gel permeation chromatography. The two methods were in fair agreement.

Publication Title

ACS Symposium Series

Volume

467

First Page

276

Last Page

290

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