Fast Field Cycling Research Articles

Lyotropic Aqueous 2-Picolinium Ionic Liquid Crystals and Their Shear-Induced Foams.

1-Dodecyl-2-methylpyridinium bromide ([C12-2-Pic][Br]) and 1-hexadecyl-2-methylpyridinium bromide ([C16-2-Pic][Br]) are two ionic liquid crystals presenting thermotropic smectic phases above 80 °C. Aiming to take advantage of the liquid crystalline properties at lower temperatures, lyotropic aqueous systems were prepared from these two organic salts. Both systems were characterized by polarized optical microscopy (POM), X-ray powder diffraction (XRD), and fast field cycling nuclear magnetic resonance (FFC-NMR) relaxometry to assess their texture, phase structure, and molecular dynamics, respectively. The mesomorphic behavior was induced at room temperature. Moreover, the lyotropic [C12-2-Pic][Br]aq revealed a smectic phase with higher separation between layers, different from the lamellar phases found in the thermotropic system (S1 and SA), which is thermally stable up to 50 °C. Furthermore, the surfactant nature of the ionic liquids diluted solutions investigated in this work allowed the formation of foams. It was found that the precursor solutions of the lyotropic dilutions with the longest alkyl chain ([C16-2-Pic][Br]aq) originated liquid foams with more stable structures than those of [C12-2-Pic][Br]aq.

Detecting soil hydrological connectivity in a badland area by fast field cycling nuclear magnetic resonance relaxometry

AbstractThe ‘hydrological connectivity inside the soil’ refers to both the spatial pattern inside the soil (structural component) and the physical–chemical process at a molecular level (functional component). Fast field cycling (FFC) nuclear magnetic resonance (NMR) relaxometry allows for measuring structural and functional connectivity by two suitable indexes named structural connectivity index (SCI) and functional connectivity index (FCI). In this study, FFC NMR relaxometry was applied to soils sampled in a very degraded environment (i.e., a badland area) to detect the capability of the measurement technique to distinguish the hydrological connectivity of these samples having different conditions (layer explored by roots, sparsely‐vegetated and bare soil). The relaxograms measured by the FFC NMR, using Proton Larmor frequencies in the range 0.01–10 MHz, were integrated and the resulting S‐shaped curves were analysed to obtain the connectivity indexes. Results showed that the ‘Sparsely vegetated’ sample is characterized by more small‐sized pores than the ‘Rooted’ one. The comparison between the ‘Sparsely vegetated’ and ‘Bare’ conditions pointed out that the presence of vegetation reduces the measured relaxation times and, as a consequence, the corresponding pore sizes and modifies the structural connectivity. The analysis also revealed that the three samples are characterized by similar values of SCI, which are independent of the proton Larmor frequency, while the FCI values of the ‘Bare’ soil are the lowest. Conversely, samples from soil with vegetation (‘Rooted’ and ‘Sparsely vegetated’) present comparable functional connectivity. Finally, the analysis of the frequency distribution of the ratio of each connectivity index and its mean value (SCI/m(SCI) and FCI/m(FCI)) allowed to establish its normal distribution. For the investigated samples, this result established that FCI and SCI can be represented by their mean value.

Fast Field-Cycling Nuclear Magnetic Resonance Relaxometry of Perfluorosulfonic Acid Ionomers and Their Perfluorosulfonyl Fluoride Precursors Membranes.

The spin-lattice relaxation rates (R1) of fluorine nuclei in perfluorosulfonic acid (PFSA) ionomer membranes and their precursor solid perfluorosulfonyl fluoride (PFSF) were measured by fast field-cycling (FFC) NMR relaxometry. The XRD profiles of PFSA and PFSF are similar and show a characteristic peak, indicating the alignment of main chains. While the SAXS profiles of the PFSA membranes show two peaks, those of the solid PFSF lack the ionomer peak which is characteristic of hydrophilic side chains in the PFSA ionomer membranes. The Larmor frequency dependence of R1 obeys power law and the indices are dependent on the sample and temperature. The indices of the PFSA membranes change from -1/2 to -1 along with the Larmor frequency and temperature dependence decrease, which is consistent with the generalized defect diffusion model. Estimated activation energies are in good agreement with those obtained from dynamical mechanical analysis and dielectric spectroscopy, indicating the segmental motion of the backbones as the common origin of these observations. On the other hand, the index changes to -3/4 in the case of the PFSFs, which has been predicted by the reptation model.

Chain dynamics of alternating polymers P(C n EG4)

Alternating or sequence defined polymers attract the attention of an increasing number of researchers recently. Due to their different blocks, they are very customizable and material properties can be tuned. In this publication, we present dynamical studies with focus on polymer dynamics, investigated by rheology and fast field cycling (FFC) NMR. The molecular weight dependencies of the relaxation time and zero-shear viscosity could hint to entanglement effects; however, the spectral shape of the viscoelastic data resembles the polymer dynamics of unentangled melts. Taking both techniques into account, i.e. rheology and FFC NMR leads to the conclusion that the relaxation spectra of the alternating polymer are similar to those of linear polymers.

Exploring Crystal-Phase Molecular Dynamics of the Low-Viscous Mesogen 6CHBT: A Combined FFC and High-Field NMR Relaxometry Investigation.

The molecular dynamics study of thermotropic mesogens exhibiting the crystal phases is valuable in unraveling the complex global (collective) and local (noncollective) motions executed by liquid crystal molecules, which would further advance the existing knowledge on orientationally disordered crystalline (ODIC) phases. Toward the fulfillment of such a task, a combined nuclear magnetic resonance (NMR) relaxometry approach employing the fast field cycling (FFC) NMR (10 kHz-30 MHz) and high-field pulsed NMR (400 MHz) techniques is utilized to sample the broad frequency range offered by molecular motions in the crystal phase of 4-(trans-4'-n-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT). The validity of the observed relaxation data is tested and interpreted by the Bloembergen-Purcell-Pound (BPP) model involving the superposition of four mutually independent Lorentzian spectral densities, reflecting molecular dynamical processes on different time scales. The salient feature of the detailed analysis reveals that the lengthening of temporal dynamics in the crystal phase due to molecular rotations by jumps, which are of intermolecular origin, is evident and further supports the presence of collective-like local dynamics. The analysis does permit decoupling of the molecular reorientations about their short axes (∼100 ns) as well as long axes (∼50 ns) and methyl group rotations (∼0.5 ns) on distinct time scales. The activation energies for reorientations about the short axes and methyl group rotations are found to be 27.3 ± 2.7 and 15.8 ± 1.1 kJ/mol, respectively. The fast methyl rotations in the crystal phase of 6CHBT obtained from FFC NMR are further well complemented by high-field NMR, where 1H NMR line shapes are relatively narrow when compared to those of the nematic phase.

Study of the surface, rheological and morphological characteristics of isotactic polypropylene microplastics aged in a photothermal oxidation chamber

The aim of this study was to investigate, in addition to degradation processes, the rheological, crystalline, and molecular dynamics changes in isotactic polypropylene microplastics with average sizes of 0.5 and 2 mm, aged in a photothermal oxidation chamber for 166 days. In addition to commonly used techniques in microplastics research, time-domain nuclear magnetic resonance (TD-NMR) in fast field cycling and fixed field modes, was employed for the first time in the study of these materials, providing non-destructive information that supports other results. Concurrently with X-ray diffractometry (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), rheometry, Fourier-transform infrared spectroscopy (FTIR), surface wettability, and scanning electron microscopy (SEM) techniques, two antagonistic phenomena were observed over the aging period. One associated with the surface degradation of microplastics and increased molecular mobility, and the other related to morphological changes in the internal layers, leading to increased rigidity. These phenomena occur slightly differently depending on the average particle size. Through multivariate data analysis with principal component analysis (PCA) and hierarchical cluster analysis (HCA), it was possible to determine that the degradation process intensifies after 62 days of simultaneous exposure to ultraviolet radiation, temperature, and oxidizing atmosphere. The obtained data highlight that even synthetic polymers with long degradation periods can undergo, in the form of microplastics, initial morphological changes in just 15 days and degradation processes within a few months of exposure to weathering conditions.

Vegan and sugar-substituted chocolates: assessing physicochemical characteristics by NMR relaxometry, rheology, and DSC

The main physicochemical characteristics of novel artisanal chocolates (both dark and milky) intended for vegan consumers or for those requiring assumption of fewer simple sugars, were analysed. Replacement of milk (with coconut copra, almonds, and soy protein isolates), and sucrose (with coconut sugars, stevia and erythritol, respectively) in dark chocolate, were accounted for by means of texture analysis, rheology, water activity, fatty acid composition, differential scanning calorimetry (DSC) and fast field cycling (FFC) nuclear magnetic resonance (NMR) relaxometry. The vegan sample (i.e., the milk-less one) showed lower values of hardness and adhesiveness as well as a larger peak in the melting behavior at the calorimetric evaluation (DSC). Moreover, the absence of milk resulted in the halving of the yield stress and a decrease in both the apparent and Casson’s viscosity. In the sample of chocolate with less sucrose, the peak temperatures measured at the DSC indicate crystallization of cocoa butter in its best form (Vβ2), unlike in dark chocolate, due to the different sugar composition. Similarly, the Casson yield stress (τ0), increased significantly (almost 70%), with the substitution of sugar. Finally, the results of NMR FFC relaxometry made it possible to identify aggregates of different sizes, laying the basis for its use as a rapid, non-destructive method for chocolate analysis.

Fast-Field Cycling Nuclear Magnetic Resonance relaxometer's electromagnet with optimized homogeneity and reduced volume

In this article a Fast Field Cycling (FFC) Nuclear Magnetic Resonance (NMR) electromagnet with low power consumption (less than 200 W), high field homogeneity and reduced volume is projected and described. The electromagnet is iron and copper based, possessing a high permeability and allowing for good magnetic field homogeneity in the operating range of 0 to 0.33 T. With this solution, it is possible to increase 65% the maximum magnetic field keeping the magnetic field homogeneity in comparison with former similar FFC relaxometers. Electromagnet's experimental and simulation results evaluating the generated magnetic field, field homogeneity, heating effects and cooling requirements are also presented. In addition, some technical aspects of the required coupled systems such as the cooling, sample heating are assessed.

Design Overview of a Toroidal Fast-Field Cycling electromagnet

In this paper, the design and development of a novel Fast-Field Cycling (FFC) Nuclear Magnetic Resonance (NMR) relaxometer’s electromagnet is described. This magnet is tailored to increase the relaxometers’s usability, by increasing its portability capacities. It presents a compact toroidal shaped iron core, allowing to operate in a field range of 0 to 0.21 T, with high field homogeneity (less than 800 ppm in a volume of ≈ 0.57 cm3 ), low power consumption and reduced losses (about 40W). The simulation software COMSOL Multiphysics® is used to characterize the induced magnetic field, the heating and the cooling effects. The proposed optimized layout constitutes an innovative solution for FFC magnets.

Water Dynamics in Dextran-Based Hydrogel Micro/Nanoparticles Studied by NMR Diffusometry and Relaxometry.

Water dynamics in mesoporous dextran hydrogel micro/nanoparticles was investigated by means of nuclear magnetic resonance (NMR) techniques. High-resolution 1H NMR spectra and pulsed field gradient (PFG) NMR diffusometry measurements obtained on swollen state dextran micro/nanogel revealed the existence of different fractions of water molecules based on their interaction with the gel matrix. In addition to the translational diffusion of bulk water, two more diffusion processes characterized with self-diffusion coefficients 1 and 2 orders of magnitude smaller than that of bulk water were identified. 1H spin-lattice relaxation dispersion profiles obtained for a broad range of Larmor frequencies using fast field cycling (FFC) and conventional NMR relaxometry techniques allowed us to further clarify the mechanisms of molecular motion. According to the water proton pool fractions and associated self-diffusion coefficients, it is shown that the relaxation contribution associated with reorientation-mediated translational motions (RMTDs) dominates the relaxation dispersion observed at intermediate frequencies. At very low frequencies, the spin-lattice relaxation rate is dominated by the slow solid-gel dynamics probed by the water molecules interacting with the pores' surface hydroxyl groups due to the rapid chemical exchange between surface hydroxyl groups and free water. The correlation time for the thumbling-like motion of the dextran gel was found to be in the submillisecond range. The values of the self-diffusion and coherence lengths associated with motion of water molecules interacting with the solid-gel particles are consistent with the particle size and pore size distributions obtained for the studied dextran gels.

Effects of deacetylation degree of chitosan on the structure of aerogels

Chitosan aerogels, obtained by (supercritical) CO2 drying of hydrogels, are novel adsorbents because of their large surface area and high porosity. Intrinsic properties of chitosan such as molecular weight (MW) and degree of deacetylation (DDA) had large impacts on the characteristics of chitosan aerogels. Although there are a few studies about the effects of solely DDA or MW on aerogel structure, none of them has focused on the mutual effects. The study aims to investigate the combined effects of MW and DDA of chitosan on aerogel properties. Hydrogels were produced in beads form by physical gelation of the chitosan solutions (2 % w/v in acetic acid of 1 %, v/v) in an alkaline environment (NaOH, 4 N). Supercritical CO2 dried aerogels were examined with respect to the bulk density, diameter as well as pore characteristics, and surface area by Barrett-Joyner-Halenda (BJH) and Brunauer-Emmett-Teller (BET) methods, respectively. Morphologies of aerogels were also examined by Scanning Electron Microscopy (SEM) images and structural changes of aerogels were observed by Fourier Transform Infrared (FTIR) Spectroscopy. Additional to BET-BJH analysis, proton relaxation dispersion was measured by Fast Field Cycling NMR (FFC-NMR) to determine the pore volume of the aerogels. Compact structures were obtained for higher MW chitosan and lower MW chitosans with higher DDA increasing the aerogel diameters. All types of aerogels obtained by different chitosan characteristics (MW and DDA) showed a porous structure and the highest DDA with the lowest MW caused the minimum bulk density with the highest water absorption rate. Although different N2 adsorption-desorption profiles were obtained in terms of pore volumes; all aerogels had Type IV isotherms with Type H1 hysteresis curve. FFC-NMR experiments showed that the coherence length values were associated with the pore volumes and FFC-NMR experiments were found to be meaningful as supportive experiments for the characterization of aerogels.

A New Model for Solving Hydrological Connectivity Inside Soils by Fast Field Cycling NMR Relaxometry

In this paper, a new quantitative approach for estimating the structural and functional connectivity inside soil by Fast Field Cycling (FFC) NMR relaxometry is presented, tested by measurements carried out in three samples with different texture characteristics. Measurements by FFC NMR relaxometry have been carried out using water-suspended samples and Proton Larmor frequencies (νL) ranging in the 0.015–35 MHz interval. Two non-degraded soil samples, with different textural characteristics, and a degraded soil collected in a badland area, were analyzed. For a given soil and any applied Proton Larmor frequency, the distribution of the longitudinal relaxation times, T1, (i.e., relaxogram) measured by FFC NMR has been integrated, and the resulting S-shaped curve (i.e., relaxogram integration curve) was represented, for the first time, by Gumbel’s diagram. This new representation of the relaxogram integration curve, transforming the S-shaped curve into a straight line, allowed for distinguishing three linear components, corresponding to three different relaxation time ranges, characterized by three different slopes. Two points, identified by the abrupt slope changes of the relaxogram integration curve plotted in Gumbel’s diagram, are used to identify two characteristic values of relaxation time, T1A and T1B, which define three well-known pore size classes (T1 < T1A micro-pores, T1A < T1 < T1B meso-pores, and T1 > T1B macro-pores). The relaxogram integration curve allowed for calculating the non-exceeding empirical cumulative frequency, F(T1), corresponding to the characteristic T1A and T1B values. The analysis demonstrated that the relaxogram can be used to determine the pore-size ranges of each investigated sample. Finally, using the slope values of the three components of the relaxogram integration curve, a new definition of the Structural Connectivity Index, SCI, and Functional Connectivity Index, FCI, was proposed.

Broadband NMR Relaxometry as a Powerful Technique to Study Molecular Dynamics of Ionic Liquids.

Fast field cycling nuclear magnetic resonance (FFC NMR) relaxometry technique has been demonstrated to be a useful analytical tool to investigate molecular dynamics in very diverse systems during the last decades. Of particular importance has been its application in studying ionic liquids, upon which this review article is based. Some of the research carried out on ionic liquids during the last ten years using this technique is highlighted in this article with the aim of promoting the favorable features of FFC NMR applied toward understanding dynamics of complex systems.

Advanced insight on the water dynamics of anisotropic hydrogels by field-cycling nuclear magnetic resonance: Application of 3-Tau model

Fast field cycling (FFC) nuclear magnetic resonance (NMR) relaxometry is used to investigate an anisotropic polygalacturonate hydrogel formed by the diffusion of calcium ions from an external reservoir (external gelation). Such a hydrogel has a gradient of polymer density accompanied by a gradient of the mesh size of its 3D network. The NMR relaxation process is dominated by the interaction of proton spins between water molecules located at polymer interfaces and in nanoporous spaces. The FFC NMR experiment provides the spin-lattice relaxation rate R1ω as a function of Larmor frequency ω producing dispersion (NMRD) curves that are highly sensitive to the dynamics of the protons at the surfaces. The hydrogel is sliced into three parts and the NMR profile for each hydrogel slice is measured. The NMRD data for each slice is interpreted using the 3-Tau Model with the aid of user-friendly fitting software called 3TM. The key fit parameters include three nano-dynamical time constants and the average “mesh size” which collectively determine the bulk water and water surface layer contribution to the total relaxation rate. The results are consistent with independent studies where comparison is possible.

Radicals on the silica surface: probes for studying dynamics by means of fast field cycling relaxometry and dynamic nuclear polarization

Determining the dynamics of adsorbed liquids on nanoporous materials is crucial for a detailed understanding of interactions and processes on the solid-liquid interface in many materials and porous systems. Knowledge of the influence of the presence of paramagnetic species on the surface or within the porous matrices is essential for fundamental studies and industrial processes such as catalysts. Magnetic resonance methods, such as electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR) and dynamic nuclear polarization (DNP), are powerful tools to address these questions and to quantify dynamics, electron-nuclear interaction features and their relation to the physical-chemical parameters of the system. This paper presents an NMR study of the dynamics of polar and nonpolar adsorbed liquids, represented by water, n-decane, deuterated water and nonane-d20, on the native silica surface as well as silica modified with vanadyl porphyrins. The analysis of the frequency dependence of the nuclear spin-lattice relaxation time is carried out by separating the intra- and intermolecular contributions, which were analyzed using reorientations mediated by translational displacements (RMTD) and force-free-hard-sphere (FFHS) models, respectively.

Ionic liquid dynamics and electrical conductivity under confinement within micro and nanocellulose ionogels

To investigate the effect of cellulose matrix on the diffusion and conductivity properties of the ionogels formed with the BMIMCl ionic liquid (IL), two types of samples were made with micro (CMC) and nano (CNC) cellulose. The cellulose interactions with IL were studied by 1H and 13C NMR solid-state spectroscopy. The cation [BMIM]+ self-diffusion coefficient was calculated based on Fast Field Cycling 1H NMR relaxation measurements. The ionic conductivity was measured by the thermal scanning conductometry method. The NMR spectra at room temperature revealed that cation in the CNC-based ionogel interacts more strongly with the cellulose chain than in the CMC-based ionogel through the methyl group at the end of the alkyl chain. Despite this, the cellulose matrix's influence on the cations' dynamics and electrical conductivity are comparable in both ionogels. The diffusion coefficient is reduced by about two times and the conductivity by about 30% compared with bulk IL.

An automatic [formula omitted]-based regularization method for the analysis of FFC dispersion profiles with quadrupolar peaks

Fast Field-Cycling Nuclear Magnetic Resonance relaxometry is a non-destructive technique to investigate molecular dynamics and structure of systems having a wide range of applications such as environment, biology, and food. Besides a considerable amount of literature about modeling and application of such technique in specific areas, an algorithmic approach to the related parameter identification problem is still lacking. We believe that a robust algorithmic approach will allow a unified treatment of different samples in several application areas. In this paper, we model the parameters identification problem as a constrained L1-regularized non-linear least squares problem. Following the approach proposed in [Analytical Chemistry2021 93 (24)], the non-linear least squares term imposes data consistency by decomposing the acquired relaxation profiles into relaxation contributions associated with 1H−1H and 1H−14N dipole-dipole interactions. The data fitting and the L1-based regularization terms are balanced by the so-called regularization parameter. For the parameters identification, we propose an algorithm that computes, at each iteration, both the regularization parameter and the model parameters. In particular, the regularization parameter value is updated according to a Balancing Principle and the model parameters values are obtained by solving the corresponding L1-regularized non-linear least squares problem by means of the non-linear Gauss-Seidel method. We analyse the convergence properties of the proposed algorithm and run extensive testing on synthetic and real data. A Matlab software, implementing the presented algorithm, is available upon request to the authors.

Physicochemical characterization of green sodium oleate-based formulations. Part 3. Molecular and collective dynamics in rodlike and wormlike micelles by proton nuclear magnetic resonance relaxation

HypothesisSodium oleate (NaOL) self-aggregates in water forming rodlike micelles with different length depending on NaOL concentration; when KCl is added wormlike micelles form, which entangle giving rise to a viscoelastic dispersion. It is expected that aggregates with different size and shape exhibit different internal and overall molecular motions and collective dynamics. ExperimentsTwo low viscosity NaOL/water and two viscoelastic NaOL/KCl/water formulations with different NaOL concentration (0.23 and 0.43 M) were investigated by 1H fast field cycling NMR relaxometry over broad temperature and Larmor frequency ranges, after a first screening by 1H and 13C NMR spectroscopy at high frequency. FindingsThe analysis of the collected data indicated that fast conformational isomerization and rotation of NaOL about its long molecular axis and lateral diffusion of NaOL around the axis of the cylindrical aggregates are slightly affected by the aggregate shape and length. On the other hand, fluctuations of the local order director are quite different in the fluid and viscoelastic systems, reflecting the shape and size of the aggregates. Quantitative information was obtained on activation energy for fast internal and overall motions, correlation times and activation energy for lateral diffusion, and coherence length for collective order fluctuations.

(Digital Presentation) Fundamentals of Deep Eutectic Solvents As Electrolytes for Lithium-Ion Batteries

Deep eutectic solvents (DESs) have emerged as an alternative to both common organic solvents and ionic liquids (ILs). DESs share physicochemical properties with ILs such as low vapor pressure, high thermal stability, high viscosity while offering advantages such as low toxicity, lower cost, and ease of preparation. Moreover, DESs are attractive candidates for electrochemical applications due to their large voltage windows and solubility properties. DESs as a solvent class share a general composition of a hydrogen bond donor (HBD), typically a polyol, amide, or acid, and a hydrogen box acceptor (HBA), usually a quaternary ammonium or phosphonium salt. At a specific molar composition of a HBD and HBD, the DES forms a eutectic mixture resulting in a large melting point depression due to extensive hydrogen bonding between the components.Despite being widely studied, the microscopic structures of DESs have remained largely uncharacterized. Herein, we present a multitechnique NMR study of two DESs: glyceline (glycerol + choline chloride) and ethaline (ethylene glycol + choline chloride). Fast-field cycling 1H relaxometry, pulsed field gradient diffusion, nuclear Overhauser effect spectroscopy (NOESY), 13C NMR relaxation, and pressure-dependent NMR experiments are deployed to sample a range of frequencies and modes of motion of the polyol and choline components of the DES. Generally, translational and rotational diffusion of polyols are more rapid than those of choline while short-range rotational motions observed from 13C relaxation indicate slow local motion of glycerol at low choline chloride (ChCl) content. We show how the additional hydroxyl group present in glycerol contributes to not only higher viscosities, but a larger perturbation of the hydrogen bonding network by the addition of ChCl.Additionally, we have investigated the solubility properties of several lithium salts (LiTFSI, LiFSI, LiPF6, LiBF4, and LiOAc) in these DESs and utilized the same suite of NMR techniques to understand how they act as solvents. We observe that due to anion effects, the heterogeneities present in DES result in differential solvation for some species where there is a distinction of lithium salts co-existing in these holes as well as the bulk. The large changes in the structural organization of DESs that result from the presence of lithium salts will serve as a guide to the design of a new class of electrolytes for lithium-ion batteries.

Molecular Dynamics of Ionic Liquids from Fast-Field Cycling NMR and Molecular Dynamics Simulations.

Understanding the connection between the molecular structure of ionic liquids and their properties is of paramount importance for practical applications. However, this connection can only be established if a broad range of physicochemical properties on different length and time scales is already available. Even then, the interpretation of the results often remains ambiguous due to the natural limits of experimental approaches. Here we use fast-field cycling (FFC) to access both translational and rotational dynamics of ionic liquids. These combined with a comprehensive physicochemical characterization and MD simulations provide a toolkit to give insight into the mechanisms of molecular mechanics. The FFC results are consistent with the computer simulation and conventional physicochemical approaches. We show that curling of the side chains around the positively charged cationic core is essential for the properties of ether-functionalized ionic liquids, and we demonstrate that neither geometry nor polarity alone are sufficient to explain the macroscopic properties.