Williamson, NH;
Röding, M;
Miklavcic, SJ;
Nydén, M;
(2017)
Scaling exponent and dispersity of polymers in solution by diffusion NMR.
J Colloid Interface Sci
, 493
pp. 393-397.
10.1016/j.jcis.2017.01.058.
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Abstract
Molecular mass distribution measurements by pulsed gradient spin echo nuclear magnetic resonance (PGSE NMR) spectroscopy currently require prior knowledge of scaling parameters to convert from polymer self-diffusion coefficient to molecular mass. Reversing the problem, we utilize the scaling relation as prior knowledge to uncover the scaling exponent from within the PGSE data. Thus, the scaling exponent-a measure of polymer conformation and solvent quality-and the dispersity (Mw/Mn) are obtainable from one simple PGSE experiment. The method utilizes constraints and parametric distribution models in a two-step fitting routine involving first the mass-weighted signal and second the number-weighted signal. The method is developed using lognormal and gamma distribution models and tested on experimental PGSE attenuation of the terminal methylene signal and on the sum of all methylene signals of polyethylene glycol in D2O. Scaling exponent and dispersity estimates agree with known values in the majority of instances, leading to the potential application of the method to polymers for which characterization is not possible with alternative techniques.
| Type: | Article |
|---|---|
| Title: | Scaling exponent and dispersity of polymers in solution by diffusion NMR. |
| Location: | United States |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.jcis.2017.01.058 |
| Publisher version: | http://dx.doi.org/10.1016/j.jcis.2017.01.058 |
| Language: | English |
| Additional information: | © 2016. This manuscript version is published under a Creative Commons Attribution Non-commercial Non-derivative 4.0 International licence (CC BY-NC-ND 4.0). This licence allows you to share, copy, distribute and transmit the work for personal and non-commercial use providing author and publisher attribution is clearly stated. Further details about CC BY licences are available at http://creativecommons.org/licenses/by/4.0. Access may be initially restricted by the publisher. |
| Keywords: | DOSY, End-group analysis, Flory exponent, Gamma distribution, Lognormal distribution, Molar mass, Molecular weight distribution, Nuclear Magnetic Resonance spectroscopy, Polydispersity Index, Polymers, Pulsed field gradient, Pulsed gradient spin echo, Scaling law, Self-diffusion |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1540168 |
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