Proton spin dynamics in polymer melts: New perspectives for experimental investigations of polymer dynamics

Abstract

The proton spin dynamics in polymer melts is determined by intramolecular and intermolecular magnetic dipole-dipole contributions of proton spins. During many decades it was postulated that the main contribution is a result of intramolecular

Application of proton field‐cycling NMR relaxometry for studying translational diffusion in simple liquids and polymer melts

“…Field‐cycling (FC) nuclear magnetic resonance (NMR) relaxometry is a well‐established method for probing the molecular dynamics in condensed matter . The method yields the (Larmor) frequency dependence (dispersion) of the spin–lattice relaxation rate R 1 ( ω ) = 1/ T 1 ( ω ).…”

“…It was argued that due to the strong distance dependence of the dipolar coupling, one can neglect intermolecular effects. However, recent FC NMR results demonstrate that intermolecular relaxation must not be ignored . Instead, it even dominates the total relaxation at low frequencies in systems such as viscous liquids and polymer melts and sometimes also in molecular crystals, here due to vacancy diffusion .…”

Dynamic Nuclear Polarization Fast Field Cycling Method for the Selective Study of Molecular Dynamics in Block Copolymers

“…FFC relaxometry has applications in a wide range of scientific fields. Since the 1990s, experiments and theoretical models of molecular motions in polymers systems, obtained by using FFC, have been devoted to the study of simple linear polymer melts . The Rouse and reptation models have been intensely studied and developed by these experiments.…”

“…Since the 1990s, experiments and theoretical models of molecular motions in polymers systems, obtained by using FFC, have been devoted to the study of simple linear polymerm elts. [24,25] The Rouse [26] and reptation models [27] have been intensely studied and developedb yt hese experiments. Despite qualitative improvements in hardware and methods for FFC measurements, the main limitation of FFC relaxometry remains in its comparatively low thermal equilibrium magnetization due to limited polarization and detection fields and relatively high sample volumes; this has left dilute systems, and extensive studies of multiexponentials ignal decays, out of the reach of FFC, anda tt he same time restricted FFC applications mostly to abundant and sensitive nuclei, such as 1 Ha nd 19 F. FFC relaxometry enhanced by DNP [19] is ap romising new methodf or selectivep olarization and increased signal-to-noise ratio, which allows one to obtain more precise data aboutm olecular dynamic in complexs ystems.…”

Glassy and Polymer Dynamics of Elastomers by 1H-Field-Cycling NMR Relaxometry: Effects of Fillers

“… 47 , 48 Thereby, different dependences of R 1 on the frequency are found in different regimes, depending on the relative weight of the intra- and interchain contributions. 46 − 48 , 61 Since glassy dynamics is strongly prevalent over polymer dynamics, 44 the latter can only be correctly investigated after separation of these two components in FC NMR data, as pointed out by Rössler and co-workers. 45 , 47 , 62 − 68 …”