Measurement of Spin Diffusion Coefficients in Glassy Polymers: Failure of a Simple Scaling Law

✍ Scribed by Bernard Meurer; Gilbert Weill

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 172 KB
• Volume: 209
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200700297

✦ Synopsis

Abstract

For a series of polymers, the spin diffusion coefficients D do not scale as predicted from a simple expression based on regularly spaced nuclei. We compare D for PVA and polystyrene with their side group either protonated or deuterated. For polystyrene, D is considerably reduced from 600–800 to 65 nm^2^ · s^−1^. For PVA, D is already small for the fully protonated chain and is only slightly reduced from 170 to 130 nm^2^ · s^−1^. This indicates that the rapidly rotating methyl group does not contribute appreciably to spin diffusion between neighboring chains and confirms that the mean proton density is not the pertinent parameter to control D.

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