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NMR methods were applied for lubricant analysis. Different factors influence the real aging of lubricants on diverse length scales and are captured by NMR. Chemical conversion of additives is addressed by NMR spectroscopy. High‐field NMR experiments allow the identification and quantification of chemical components and are transferred to benchtop devices. Molecular dynamics and contaminations like fuel or abrasion are addressed via NMR relaxation and diffusion. Quality parameters were extracted via suitable data analysis of NMR raw data, which allow the detection of aging and indicate changes in the oil composition. At the same time, the methodology is optimized to the conditions in quality control. The feasibility is shown the example of a series of lubricants from applications in regenerative energy production, namely, wind turbine oils and biogas motor oils. [ABSTRACT FROM AUTHOR]

The crystallization of melt emulsions is of great interest to the food, cosmetic, and pharmaceutical industries. Surfactants are used in emulsions and suspensions to stabilize the dispersed phase; thus, questions arise about the liquid–liquid and solid–liquid interfaces of the droplets or particles and the distribution of the surfactant in the different phases (continuous and dispersed phase, interface). Nuclear magnetic resonance relaxation and diffusion measurements revealed that the internal and rotational mobility of surfactant molecules at the liquid–liquid interface decreases with increasing droplet sizes. Additionally, solid–liquid interfaces have fewer surfactants than liquid–liquid interfaces as a result of the desorption of the surfactant molecules during the crystallization of the droplets. Relaxation rates of surfactant molecules in aqueous solution as single molecules, micelles, and at the liquid–liquid and solid–liquid interface are analyzed for the first time. [ABSTRACT FROM AUTHOR]

Increasing the efficiency of disperse phase crystallization is of great interest for melt emulsion production as the fraction of solidified droplets determines product quality and stability. Nucleation events must appear within every single one of the μm‐sized droplets for solidification. Therefore, primary crystallization requires high subcooling and is, thus, time and energy consuming. Contact‐mediated nucleation is a mechanism for intensifying the crystallization process. It is defined as the successful nucleation of a subcooled liquid droplet induced by contact with an already crystallized droplet. We investigated contact‐mediated nucleation under shear flow conditions up to shear rates of 457 s−1 for a quantitative assessment of this mechanism. Rheo‐nuclear magnetic resonance was successfully used for the time‐resolved determination of the solids fraction of the dispersed phase of melt emulsions upon contact‐mediated nucleation events. The measurements were carried out in a dedicated Taylor–Couette cell. The efficiency of contact‐mediated nucleation λsec decreased with increasing shear rate, whereas the effective second order kinetic constant kcoll,eff increased approximately linearly at small shear rates and showed a linear decrease for shear rates higher than about 200 s−1. These findings are in accordance with coalescence theory. Thus, the nucleation rate is optimal at specific flow conditions. There are limitations for successful inoculation at a low shear rate because of rare contact events and at a high shear rate due to too short contact time. [ABSTRACT FROM AUTHOR]

Lubricating greases were investigated by nuclear magnetic resonance/magnetic resonance imaging (NMR/MRI) to get insight into their structure and into their response to mechanical forces, which is related to bleeding and aging. The investigated greases are based on metallic soaps of fatty acids and oils, whereby LiOH is often used. These organic soaps act as thickeners and provide a network in which oils and their additives are embedded. Lubricating greases can thus be considered as a class of substances similar to oleogels or even hydrogels. Questions arise about translational mobility of guest molecules, mainly base oil, in these networks. Molecular structuring and interactions within the network of thickeners are of interest as they are related to macroscopic stability. Apart from NMR spectroscopy (1H‐, 7Li‐ and 31P‐NMR), spectrally resolved relaxation and diffusion measurements are used for characterization. In addition, magic angle spinning (MAS)‐NMR was combined with 1H‐MRI to investigate the impact of mechanical stress and swelling of lubricating greases. [ABSTRACT FROM AUTHOR]

Summary Due to the versatile applications of the non‐destructive and non‐invasive NMR methods, numerous processes such as crystallization, aging, separation and chemical reaction can be characterized in detail relying on molecular structure, molecular dynamics, diffusion and mesoscopic structures. For example, quantitative NMR‐spectroscopy is used to monitor chemical reactions. MRI, which is frequently used in medicine, can also be applied to investigate membrane filtration in order to characterize fouling. Moreover, NMR methods are applied in industry to determine product properties and product quality, e.g. to detect adulteration in food and to determine oil or fat content to name a few. [ABSTRACT FROM AUTHOR]

A dedicated nuclear magnetic resonance (NMR) sensor was designed for the analysis of liquids. The magnets are arranged in a V shape, creating a spatially dependent magnetic field in the gap. Measurements of samples with diverse diameters are possible underdefined magnetic field gradients at a given position. The magnet thus combines properties of single sided NMR with high static magnetic field gradients and classical time domain (TD) devices with lower to almost zero gradients. The sensor can easily be adapted to the requirements of the considered investigation; probes can be customized. On the example of lubricants and their aging, the added value and applicability of this sensor in quality control are highlighted in this publication. Relaxation and diffusion were measured by Carr-Purcell-Meiboom-Gill (CPMG) while varying the echo time te and quantified via numerical modeling. Especially, relaxation shows a high sensitivity towards aging of lubricants such as particulate abrasion and changes in molecular dynamics induced, for example, by additive depletion. The applicability of this NMR sensor in quality control is demonstrated on the example of engine and transmission oils as well as of lubrication greases. [ABSTRACT FROM AUTHOR]

The impact of electrode formation is studied by the spatially and time‐resolved distribution of transverse relaxation. In situ 7Li nuclear magnetic resonance experiments are performed on an experimental lithium‐ion battery cell to study the impact of electrode passivation via imaging and transverse relaxation in the interelectrode volume. The electrolyte in the battery, using technically relevant electrode material, i.e., graphite and lithium–nickel–cobalt–manganese–oxide, is studied by 2D magnetic resonance imaging. The electrolyte is 1 mol L−1 lithium hexafluorophosphate dissolved in a binary mixture of ethylene carbonate and dimethyl carbonate. 1D profiles are acquired and related to 7Li concentration during passivation and during a constant current/constant voltage cycle. The transverse relaxation rate R2(z,t) measured by multiecho profiles revealed changes within the electrolyte volume. The ongoing process changes the relaxation distribution. Indications for a defective electrode passivation are deduced from the data. During one charging cycle with constant current/constant voltage, the lithium concentration is measured spatially resolved, and the data are modeled by the Nernst–Planck equation. [ABSTRACT FROM AUTHOR]

There is a need to better understand the influence of shear flow on the crystallization of a molten oil phase in an oil/water emulsion due to its high relevance for industrial processes. The present study focuses on the influence of laminar shear flow on the crystallization kinetics of polydisperse n‐hexadecane‐in‐water emulsions. The investigation was carried out by rheo‐nuclear magnetic resonance (NMR) spectroscopy in a Taylor‐Couette geometry. An accelerating impact of the shear rate on the overall crystallization kinetics was verified. This effect stems from an increase of the collision frequency of already crystallized droplets with not yet crystallized droplets. Nevertheless, the collision efficiency decreased with higher shear rate. [ABSTRACT FROM AUTHOR]

The water loss in packed beds was studied spatially and time‐resolved via magnetic resonance imaging on the pore scale. The packed beds were measured under water‐saturated and unsaturated conditions, while the magnetic resonance method allowed a quantitative differentiation between air, liquid, and solid phases exploring the native contrast of the named phases without additional contrast agents. Beside a qualitative image comparison, subsequent quantitative image processing allowed for a detailed spatially resolved determination of water distribution, the differentiation between water transport processes, and the quantification of liquid clusters in 3‐D. Results are presented for two packed beds that show significant differences in their evaporation and drainage dynamics, which are mainly determined by the physical properties of the packed beds. The water loss of the packed bed of 2–4 mmquartz particles reached a level below interpretability after 18.2 hr; meanwhile, a successive decrease of the largest liquid cluster volume from 82.5 to 0.7 mm³ was observed. The water content of the packed bed of 2 mm glass spheres was still observable after 70.9 hr. During the experiment, no significant changes in the structure of the liquid clusters were measured. The current work displays the applicability of magnetic resonance imaging for porescale investigations without the addition of contrast agents. [ABSTRACT FROM AUTHOR]

Oil is a prominent, but multifaceted material class with a wide variety of applications. Technical oils, crude oils as well as edibles are main subclasses. In this review, the question is addressed how low‐field NMR can contribute in oil characterization as an analytical tool, mainly with respect to quality control. Prerequisite in the development of a quality control application, however, is a detailed understanding of the oils and of the measurement. Low‐field NMR is known as a rich methodical toolbox that was and is explored and further developed to address questions about oils, their quality, and usability as raw materials, during production and formulation as well as in use. [ABSTRACT FROM AUTHOR]

In white biotechnology research, the putative superiority of productive biofilms to conventional biotransformation processes based on planktonic cultures has been increasingly discussed in recent years. In the present study, we chose lactic acid production as a model application to evaluate biofilm potential. A pure culture of Lactobacillus bacteria was grown in a tubular biofilm reactor. The biofilm system was cultivated monoseptically in a continuous mode for more than 3 weeks. The higher cell densities that could be obtained in the continuous biofilm system compared with the planktonic culture led to a significantly increased space‐time yield. The productivity reached 80% of the maximum value 10 days after start‐up and no subsequent decline was observed, confirming the suitability of the system for long‐term fermentation. The analysis of biofilm performance revealed that productivity increases with the flow velocity. This is explained by the reduced retention time of the liquid phase in the reactor, and, thus, a minor pH drop caused by the released lactic acid. At low flow velocities, the pH drops to a value where growth and production are significantly inhibited. The biofilm was visualized by magnetic resonance imaging to analyze biofilm thickness. To deepen the understanding of the biofilm system, we used a simple model for cell growth and lactic acid production. [ABSTRACT FROM AUTHOR]

Filtration and separation via membranes are key processes in food processing. One major application of membrane filtration is in the dairy industry, aiming for the separation of different milk proteins. The various chemical components of milk possess different physiochemical properties and can be used most effectively in food processing if they are separately available and remain in their native state. Microfiltration of skim milk allows a fractionation of the milk proteins casein and whey by size. A deposit is formed on the membrane surface mainly but not exclusively by micellar casein proteins during filtration. Membrane pore blockage by whey proteins and fouling occur during membrane filtration, negatively affecting the yield of the whey protein fraction. Skim milk filtration and the deposit layer formation were measured time and spatially resolved by in situ magnetic resonance imaging (MRI). The nature of the fouling layer was investigated during dead‐end filtration in ceramic hollow fiber membranes. MRI was used to further clarify the influence of operating conditions on separation and filtration mechanisms that are responsible for growth of the fouling layer and its reversibility. The MRI measurements were analyzed for a detailed description of skim milk filtration by modeling the signal intensity distribution. [ABSTRACT FROM AUTHOR]

The polymerization of Furfuryl Alcohol (FA) was studied systematically by NMR transverse relaxation. A special focus is on the impact of nanoparticles (BTN, TMOA, and APTES) on the reaction kinetic of the resin's polycondensation. The NMR spin‐spin relaxation rate (R2) was measured by the Carr–Purcell–Meiboom‐Gill (CPMG) multiecho sequence. The molecular mobility of the resin's molecules during reaction could be followed by R2 as a function of curing time. R2 for the chain protons increased with reaction time. R2 increased faster in the presence of nanoclay, thus, nanoclay acts as a sort of catalyst in FA polymerization. The results strongly suggest that entanglements and filler‐induced packing disruption play a major role in polymer dynamics. Based on the experimental data, the curing kinetics was modeled by considering both chemical and diffusion‐controlled autocatalytic kinetic models. The order of the overall reaction was found to be approximately 2. POLYM. COMPOS., 39:3280–3288, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Abstract: Superabsorbent polymer (SAP) hydrogels have pronounced water‐absorbing and water‐storing capacities, which are essential for numerous potential applications. It remains a challenge to better understand the network topology because of their amorphous and anisotropic structures. Synthesis parameters such as monomer concentration, degree of neutralization and crosslinking, and surface crosslinking are varied to correlate structural changes in the network with low‐field proton double‐quantum (1H DQ) NMR results. 1H DQ‐NMR data are processed by a reliable, user‐independent analysis approach to determine the fractions of network defects, of mobile sol components, and of network chains as well as the residual dipolar coupling distribution in SAPs. In addition, results obtained by applying different distributions to describe the DQ buildup curves are quantified and compared. The correlation between topological and synthesis parameters as well as the impact of temperature, swelling, and solvent of SAP on DQ signals is investigated and discussed. [ABSTRACT FROM AUTHOR]

Time domain nuclear magnetic resonance (TD‐NMR) is used to determine the solid fat content (SFC) of dispersions stabilized by a high molecular weight hydrocolloid (gum arabic, GA) containing a high melting lipid (tristearin, SSS). Since the lipid is molten prior to homogenization for the preparation of the dispersion it recrystallizes during cooling and storage. It is known that the recrystallization in a disperse system differs from bulk lipids and TD‐NMR can be a helpful tool to investigate the phenomenon. SFC measurement by TD‐NMR is well established and widely used in food science for oils, spreads, and seeds. In the case of dispersions, however, the situation is more demanding due to the quasi‐continuous phase. A suitable TD‐NMR method has to account for that and can be realized when combining longitudinal and transverse relaxation properties to separate the signal contribution of the quasi‐continuous phase and the solid lipid and liquid lipid dispersed phase. Signal from water and emulsifier is eliminated by magnetization inversion with an initial 180° pulse and a subsequent dedicated inversion delay. The emulsifier shows a longitudinal relaxation similar to the aqueous phase. With a carefully chosen inversion delay, both signal contributions of water and emulsifier can be suppressed, and a quantitative determination of the SFC is possible via dedicated data processing. Practical Applications: The method can be applied in characterization, stability tests and quality control of complex food emulsions and solid lipid particles, which are recently under development as drug carrier systems. TD‐NMR is used to determine the solid fat content (SFC) of dispersions with high water content, a hydrocolloid as emulsifier and fat. Since the fat is molten prior to homogenization it recrystallizes during cooling. It is known that recrystallization in a dispersed system differs from bulk and TD‐NMR is a helpful tool to investigate the phenomenon. The situation is demanding due to the quasi‐continuous phase. With magnetization inversion, a preset 180° pulse, and a carefully chosen inversion delay, signal contributions of water, and emulsifier can be suppressed, and a quantitative determination of the SFC is possible. [ABSTRACT FROM AUTHOR]

Mass transfer in biofilms is determined by diffusion. Different mostly invasive approaches have been used to measure diffusion coefficients in biofilms, however, data on heterogeneous biomass under realistic conditions is still missing. To non-invasively elucidate fluid-structure interactions in complex multispecies biofilms pulsed field gradient-nuclear magnetic resonance (PFG-NMR) was applied to measure the water diffusion in five different types of biomass aggregates: one type of sludge flocs, two types of biofilm, and two types of granules. Data analysis is an important issue when measuring heterogeneous systems and is shown to significantly influence the interpretation and understanding of water diffusion. With respect to numerical reproducibility and physico-chemical interpretation, different data processing methods were explored: (bi)-exponential data analysis and the Γ distribution model. Furthermore, the diffusion coefficient distribution in relation to relaxation was studied by D- T2 maps obtained by 2D inverse Laplace transform (2D ILT). The results show that the effective diffusion coefficients for all biofilm samples ranged from 0.36 to 0.96 relative to that of water. NMR diffusion was linked to biofilm structure (e.g., biomass density, organic and inorganic matter) as observed by magnetic resonance imaging and to traditional biofilm parameters: diffusion was most restricted in granules with compact structures, and fast diffusion was found in heterotrophic biofilms with fluffy structures. The effective diffusion coefficients in the biomass were found to be broadly distributed because of internal biomass heterogeneities, such as gas bubbles, precipitates, and locally changing biofilm densities. Thus, estimations based on biofilm bulk properties in multispecies systems can be overestimated and mean diffusion coefficients might not be sufficiently informative to describe mass transport in biofilms and the near bulk. [ABSTRACT FROM AUTHOR]

Quantification of diffusion coefficient distribution (DCD) and correlation with molecular weight distribution (MWD) of polymers is still an issue in pulsed field-gradient nuclear magnetic resonance (PFG-NMR). The conventional scaling law utilized so far to relate diffusion coefficient and molecular weight only holds true for the determination of MWD at sufficiently low concentrations. To extend measurement limits and to get a good signal-to-noise ratio, an exponential correlation is introduced to describe the effect of polymer concentration on diffusion in PFG-NMR. Two model polymers (polystyrene and poly(methyl methacrylate)) dissolved in deuterated chloroform are studied at different concentrations in the range of 0.16-8 wt%. The DCDs are determined by modeling the measured signal attenuation with three methods (gamma distribution, log normal distribution, and tailored norm regularization). It is shown that the proposed method applies to the PFG-NMR measurements on polymer solutions over a wide concentration range, providing almost the same MWDs as those obtained at low concentrations. The MWDs retrieved from NMR experiments agree well with those by size exclusion chromatography. [ABSTRACT FROM AUTHOR]

Medium-resolution nuclear magnetic resonance spectroscopy (MR-NMR) currently develops to an important analytical tool for both quality control and process monitoring. In contrast to high-resolution online NMR (HR-NMR), MR-NMR can be operated under rough environmental conditions. A continuous re-circulating stream of reaction mixture from the reaction vessel to the NMR spectrometer enables a non-invasive, volume integrating online analysis of reactants and products. Here, we investigate the esterification of 2,2,2-trifluoroethanol with acetic acid to 2,2,2-trifluoroethyl acetate both by 1H HR-NMR (500 MHz) and 1H and 19F MR-NMR (43 MHz) as a model system. The parallel online measurement is realised by splitting the flow, which allows the adjustment of quantitative and independent flow rates, both in the HR-NMR probe as well as in the MR-NMR probe, in addition to a fast bypass line back to the reactor. One of the fundamental acceptance criteria for online MR-MNR spectroscopy is a robust data treatment and evaluation strategy with the potential for automation. The MR-NMR spectra are treated by an automated baseline and phase correction using the minimum entropy method. The evaluation strategies comprise (i) direct integration, (ii) automated line fitting, (iii) indirect hard modelling (IHM) and (iv) partial least squares regression (PLS-R). To assess the potential of these evaluation strategies for MR-NMR, prediction results are compared with the line fitting data derived from the quantitative HR-NMR spectroscopy. Although, superior results are obtained from both IHM and PLS-R for 1H MR-NMR, especially the latter demands for elaborate data pretreatment, whereas IHM models needed no previous alignment. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Hyphenated low-field NMR techniques are promising characterization methods for online process analytics and comprehensive offline studies of soft materials. By combining different analytical methods with low-field NMR, information on chemical and physical properties can be correlated with molecular dynamics and complementary chemical information. In this review, we present three hyphenated low-field NMR techniques: a combination of near-infrared spectroscopy and time-domain NMR (TD-NMR) relaxometry, online 1H-NMR spectroscopy measured directly after size exclusion chromatographic (SEC, also known as GPC) separation and a combination of rheometry and TD-NMR relaxometry for highly viscous materials. Case studies are reviewed that underline the possibilities and challenges of the different hyphenated low-field NMR methods. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Biofilms on cylindrical carrier material originating from a lab-scale moving bed biofilm reactor (MBBR) were investigated by means of Magnetic Resonance Imaging (MRI). The aim of this study was to determine the local flow velocities at the inner face of the biofilm carrier. To get an insight into the mass transport processes, flow velocity maps of blank and with biofilm cultivated carriers were measured. A single carrier was placed in a tube in three different orientations and exposed to flow velocities of 0.21, 0.42, and 0.64 mm/s. The interplay of the biofilm morphology and the local flow pattern was then analyzed including the effect of the orientation of the carrier in relation to the upstream flow angle. Within this study, the biofilm carrier can be understood as an interconnected system of four sections in which the incoming fluid volume will be distributed depending on the biomass occupation and morphology. In sections with high biofilm occupation, the flow resistance is increased. Depending on the orientation of the carrier in the flow field, this effect leads to flow evasion through less covered sections showing higher flow velocities and consequently the risk of biofilm detachment. However, there was no clear correlation between biofilm coverage and flow ratio. Biotechnol. Bioeng. 2015;112: 1023-1032. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Low-field NMR relaxometry is sensitive to molecular mobility within well-defined time windows and can thus be applied to study interactions between polymers and inorganic filler particles in composite materials. Volume fraction and dispersion of the filler influence the polymer chain dynamics, which also modify the macroscopic properties of the polymer composites. As model systems, TiO2-filled poly( n-alkyl methacrylates) with different side-chain lengths and filler contents are prepared by melt mixing. Several 1H NMR relaxation parameters, which are sensitive and selective toward polymer-filler interactions, are investigated at a Larmor frequency of 20 MHz as a function of temperature. Both physical and empirical models are used to analyze the NMR data, and the results are compared with the aim of an unambiguous detection of polymer-filler interactions. [ABSTRACT FROM AUTHOR]

Current results and limitations of a novel SEC-MR-NMR (size-exclusion chromatography-medium resolution nuclear magnetic resonance) system are presented, delivering a direct correlation of chemical structure and molecular weight. A 20 MHz 1H NMR spectrometer based on permanent magnets was combined with a SEC setup. The NMR sensitivity was improved by digital filters, shims, and a self-built flow probe when compared with time-domain instruments. For optimum NMR signal-to-noise ratio ( S/ N) of polymer fractions and concomitantly reduced S/ N of solvent signals, deuterated solvents or protonated solvents, with solvent suppression, were applied. Results are presented after optimization of both NMR and chromatographic components such as column dimension and volume flow. [ABSTRACT FROM AUTHOR]

Polystyrene solutions in CDCl3 were examined by different NMR techniques. Diffusion measurements and spectrally resolved frequency-dependent 1H longitudinal relaxation studies give some insight into the complex molecular motional modes and their frequency dependence, that is, the dispersion of the longitudinal relaxation rate. The newly available spectral resolution at low magnetic field around 20 MHz 1H-Larmor frequency additionally allows the differentiation of aliphatic and aromatic spectral contributions and, therefore, a more detailed description of the molecular mobility in the frequency range of several MHz compared to the well-known time-domain or field-cycling NMR studies. [ABSTRACT FROM AUTHOR]

Fat content is one of the important parameters of quality control in many food products. Several techniques are used to determine the amount of fat in a given product. In this work, the applicability of a portable dedicated nuclear magnetic resonance (NMR) analyzer to measure the fat content in a packaged product without destruction of the material was examined. Two different low-field NMR methods, namely, a ratio method and a relaxation time method, were applied and discussed. The processed NMR signal was linearly correlated with the fat content obtained by reference methods. The linear correlation allowed the application of single-sided NMR for fat measurements. [ABSTRACT FROM AUTHOR]

A monodisperse decamer bearing ten different side chains, obtained via the iterative Passerini three‐component reaction and subsequent deprotection, is investigated by 1H pulsed field gradient (PFG) NMR. Both the stimulated echo (PFG‐STE) and a fast spin‐echo pulse sequence (β‐PFG‐SE) are applied to explore the translational diffusion properties of the sequence‐defined decamer in solution at different concentrations with the aim of establishing an independent and new method to confirm its monodispersity. The signals decay according to the expectation of monodisperse molecules in solution with a high experimental accuracy, indeed verifying the monodispersity of these decamers. The diffusion coefficients can further be interpreted in terms of molecular weight. Both NMR methods result in comparable diffusion coefficients, while the β‐PFG‐SE reduces the experimental time by a factor of about 18. [ABSTRACT FROM AUTHOR]

Polyacrylate hydrogels PAAM (M = 7Li+, 23Na+, 39K+, 87Rb+, and 133Cs+) are synthesized by free‐radical copolymerization and are studied by Nuclear Magnetic Resonance (NMR) over wide time and length scales to get an insight into the polymer network structure and the dynamics of alkali ions and water. 1H double‐quantum NMR (1H DQ‐NMR) indicates that neutralization by different alkali ions influences the polymer structure in swollen PAAM hydrogels. Relaxation rates of alkali ions are found to be dominated by quadrupolar relaxation. 1H relaxation varies with the chain fraction obtained from 1H DQ‐NMR. Pulsed field gradient NMR reveals diffusion coefficients of alkali ions and water for different swelling degrees. Network structure and dynamics as well as the interactions between water, alkali ions, and polymer chains are discussed. [ABSTRACT FROM AUTHOR]

Front Cover: In article number 1800586, Manfred Wilhelm and co‐workers present studies on the molecular dynamics, morphology, and flow behavior of crystallizing polymers. Material properties are correlated on broad length and time scales by using hyphenations of rheology and in‐situ nuclear magnetic resonance, small angle X‐ray scattering, and optical microscopy. [ABSTRACT FROM AUTHOR]

Dynamics of sodium ions and water in swollen superabsorbent polymer (SAP) hydrogels are studied by 23Na‐ and 1H‐NMR, respectively. The apparent diffusion coefficients of water in swollen SAPs, probed by 1H pulsed field gradient NMR, decreases with increasing diffusion time. The degree of hindrance depends on structural and synthesis parameters. It is quantified within a tortuosity model. Based on the results, the swelling degree has the highest impact on the ion mobility, apart from synthesis parameters leading to different levels of physical and chemical crosslinks. 23Na‐NMR relaxation and diffusion reveal the 23Na+ mobility in swollen SAPs. A higher degree of neutralization leads to faster relaxation and to a smaller apparent diffusion coefficient. Surface crosslinking restricts water mobility, but has a smaller impact on the dynamics of sodium ions. The experimental results indicate an influence of SAP structure on the dynamics of ions and water molecules. Dynamics of 23Na+ and water in swollen superabsorbent polymers (SAPs) are probed by 23Na‐ and 1H‐NMR, respectively. The steric hindrance of the SAP network on water mobility is quantified within a tortuosity model for the 1H diffusion coefficient. 23Na‐NMR relaxation and diffusion experiments reveal 23Na+ mobility in swollen SAPs. Their mutual interactions with hydrophilic networks are explored. [ABSTRACT FROM AUTHOR]