Basic principles of static proton low-resolution spin diffusion NMR in nanophase-separated materials with mobility contrast

Schäler, Kerstin; Roos, Matthias; Micke, P.; Golitsyn, Yury; Seidlitz, Anne; Thurn‐Albrecht, Thomas; Schneider, H.; Hempel, Günter; Saalwächter, Kay

doi:10.1016/j.ssnmr.2015.09.001

Cited by 88 publications

(113 citation statements)

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“…In case of polymers with CH 2 groups, featuring a dominant coupling between the two protons, the decay time constant T 2,stat (at which the signal has decayed by about ∼65%) is of the order of 12-15 µs. 29 This characteristic T 2,stat is about twice the inverse average dipole-dipole coupling constant D HH (unit: rad/s), i.e., D −1 HH ≈ (2π × 20 kHz) −1 ≈ 8 µs. Large-angle jumps with correlation times on this time scale (τ c ≈ T 2,stat ) lead to significant changes of the shape of the FID.…”

Section: Resultsmentioning

confidence: 98%

“…Segments in such a component (subject to an increase in T g by confinement or adsorption effects) do not move significantly in lateral direction and are usually considered to be part of a contiguous sub-volume that is reasonably assumed to form a layer around the filler particles. 20 In such a dynamically inhomogeneous system, the FID can be written as a superposition, where typically no more than 3 distinct components, including an intermediate one, can be differentiated according to 28,29 FID(t)…”

Section: Resultsmentioning

confidence: 99%

“…29 for details on their choice. While the DQ-filtered signal is nonquantitative due to the impossibility to transiently convert all related signal into DQ coherences, the MAPE-filtered signal is ideally identical to the FID at longer times at which the less mobile components have decayed.…”

Section: Resultsmentioning

confidence: 99%

“…Note that the DQ-filtered data feature a small oscillation around 50 µs due to residual spin-pair character. While one could use a more complicated fitting function to capture this phenomenon, 29 we here chose to approximate it with a Gaussian, with negligible overall error. It is also stressed that T 2,m and β m can be determined from the MAPE-filtered signal with high precision despite the limited fitting range.…”

Section: Resultsmentioning

confidence: 99%

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Reduced-mobility layers with high internal mobility in poly(ethylene oxide)–silica nanocomposites

Golitsyn

Schneider

Saalwächter

2017

The Journal of Chemical Physics

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A series of poly(ethylene oxide) nanocomposites with spherical silica was studied by proton NMR spectroscopy, identifying and characterizing reduced-mobility components arising from either roomtemperature lateral adsorption or possibly end-group mediated high-temperature bonding to the silica surface. The study complements earlier neutron-scattering results for some of the samples. The estimated thickness of a layer characterized by significant internal mobility resembling backbone rotation ranges from 2 nm for longer (20 k) chains adsorbed on 42 nm diameter particles to 0.5 nm and below for shorter (2 k) chains on 13 nm particles. In the latter case, even lower adsorbed amounts are found when hydroxy endgroups are replaced by methyl endgroups. Both heating and water addition do not lead to significant changes of the observables, in contrast to other systems such as acrylate polymers adsorbed to silica, where temperature-and solvent-induced softening associated with a glass transition temperature gradient was evidenced. We highlight the actual agreement and complementarity of NMR and neutron scattering results, with the earlier ambiguities mainly arising from different sensitivities to the component fractions and the details of their mobility.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Reduced-mobility layers with high internal mobility in poly(ethylene oxide)–silica nanocomposites

Golitsyn

Schneider

Saalwächter

2017

The Journal of Chemical Physics

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“…One such approach is based on 1 H spin diffusion NMR, which has classically been utilized for degrees of mixing in blends [1, 2, 3, 4, 5, 6], and continues to be a vital analytical tool for polymer blends [7, 8], copolymers [9], pharmaceuticals [10], and dispersions [11]. Due to its high sensitivity, Combined Rotation And Multiple Pulse Spectroscopy (CRAMPS) [12] based 1 H spin diffusion is a fast method for determining degrees of miscibility.…”

Section: Introductionmentioning

confidence: 99%

On the role of experimental imperfections in constructing 1H spin diffusion NMR plots for domain size measurements

Nieuwendaal

2016

Solid State Nuclear Magnetic Resonance

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We discuss the precision of 1D chemical-shift-based 1H spin diffusion NMR experiments as well as straightforward experimental protocols for reducing errors. The 1H spin diffusion NMR experiments described herein are useful for samples that contain components with significant spectral overlap in the 1H NMR spectrum and also for samples of small mass (< 1 mg). We show that even in samples that display little spectral contrast, domain sizes can be determined to a relatively high degree of certainty if common experimental variability is accounted for and known. In particular, one should (1) measure flip angles to high precision (≈ ±1° flip angle), (2) establish a metric for phase transients to ensure their repeatability, (3) establish a reliable spectral deconvolution procedure to ascertain the deconvolved spectra of the neat components in the composite or blend spin diffusion spectrum, and (4) when possible, perform 1D chemical-shift-based 1H spin diffusion experiments with zero total integral to partially correct for errors and uncertainties if these requirements cannot fully be implemented. We show that minimizing the degree of phase transients is not a requirement for reliable domain size measurement, but their repeatability is essential, as is knowing their contribution to the spectral offset (i.e. the J1 coefficient). When performing experiments with zero total integral in the spin diffusion NMR spectrum with carefully measured flip angles and known phase transient effects, the largest contribution to error arises from an uncertainty in the component lineshapes which can be as high as 7 %. This uncertainty can be reduced considerably if the component lineshapes deconvolved from the composite or blend spin diffusion spectra adequately match previously acquired pure component spectra.

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Binder and Interphase Microstructure in a Composite Material Characterized by Scanning Electron Microscopy and NMR Spin Diffusion Experiments

Parisse

Petit

Forzy

et al. 2019

Macro Chemistry & Physics

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1H NMR spin diffusion is shown to advantageously complement scanning electron microscopy (SEM) observations for the characterization of polymer structuring in composite materials. It is here demonstrated on a material containing a few percent of polymer binder and a crystalline organic/inorganic mixture as reinforcement. In SEM observations, polymer accumulations are seen. However, the polymer is also expected to fill small porosities and thin layers at the interface of particles to ensure the cohesion and the mechanical properties of the assembly. In most cases, this polymer structuring is invisible considering the resolution and contrast achieved by SEM on such material. It is thus investigated taking advantage of the two‐step decay of nuclear magnetic resonance spin diffusion curves. Average thickness values of 30 and 188 nm are estimated for the interphase and the overall polymer, respectively. Such structural information improves the knowledge of structure/property relationships and provides better understanding of material properties and making processes.

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Basic principles of static proton low-resolution spin diffusion NMR in nanophase-separated materials with mobility contrast

Cited by 88 publications

References 50 publications

Reduced-mobility layers with high internal mobility in poly(ethylene oxide)–silica nanocomposites

Reduced-mobility layers with high internal mobility in poly(ethylene oxide)–silica nanocomposites

On the role of experimental imperfections in constructing 1H spin diffusion NMR plots for domain size measurements

Binder and Interphase Microstructure in a Composite Material Characterized by Scanning Electron Microscopy and NMR Spin Diffusion Experiments

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