Dielectric Relaxation of Water in Clay Minerals

Vasilyeva, M. A.; Gusev, Yuri A.; Штырлин, В. Г.; Greenbaum, Anna; Puzenko, Alexander; Ishai, Paul Ben; Feldman, Yuri

doi:10.1346/ccmn.2014.0620106

Cited by 42 publications

(23 citation statements)

References 42 publications

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“…The time scale of α* does not resemble any recorded dynamics in initial MMT clays. 89 It is noteworthy that a qualitatively similar dynamics view between α and α* here has been reported in previous studies of different polymers (hyperbranched polyesters, bio-based polyester polyols) intercalated between MMT nanosheets similar to ours (MMT-Na). 68,87,90 Also, the effects of crystallization on the dynamics and strength of α* here resemble those of the interfacial polymer relaxation of low M n poly-(dimethylsiloxane)s adsorbed physically at the surface of silica nanoparticles of various types.…”

Section: Thermal Transitions and Calorimetric Polymersupporting

confidence: 88%

Molecular Dynamics in Nanocomposites Based on Renewable Poly(butylene 2,5-furan-dicarboxylate) In Situ Reinforced by Montmorillonite Nanoclays: Effects of Clay Modification, Crystallization, and Hydration

et al. 2020

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This study deals with poly(butylene 2,5-furan-dicarboxylate), PBF, a renewable bio-based polyester expected to replace non-eco-friendly fossil-based homologues. PBF exhibits excellent gas barrier properties, which makes it promising for packaging applications; however, its rather low and slow crystallinity affects good mechanical performance. The crystallization of this relatively new polymer is enhanced here via reinforcement by introduction in situ of 1 wt % montmorillonite, MMT, nanoclays of three types (functionalizations). We study PBF and its nanocomposites (PNCs) also from the basic research point of view, molecular dynamics. For this work, we employ the widely used combination of techniques, differential scanning calorimetry (DSC) with broad-band dielectric relaxation spectroscopy (BDS), supplemented by polarized light microscopy (PLM) and thermogravimetric analysis (TGA). In the PNCs, the crystalline rate and fraction, CF, were found to be strongly enhanced as these fillers act as additional crystallization nuclei. The improvements in crystallization here correlate quite well with those on the mechanical performance recorded recently; moreover, they occur in the same filler order, in particular, with increasing MMT interlayer distance (from ∼1 to ∼3 nm). In the amorphous fraction of the polymer, the chain diffusion (calorimetric T g and dynamic α process) is easier in the PNCs due to their slightly smaller length, while in the semicrystalline state, it decelerates by crystal-induced constraints. The local polymer dynamics (β process, below T g) was found to be independent of the PNC composition, however, sensitive to structural changes of the matrix. Finally, a filler-induced dynamics was additionally recorded in the PNCs (α* process), arising possibly from the polymer located at the MMT surfaces. α* follows the changes in polymer chain length and decelerates with crystallization, whereas its activation energy decreases with mild hydration. The combined results on α* with the DSC and TGA findings, provide proof for weak MMT–PBF interactions. Overall, our results, along with data from the literature, suggest that such furan-based polyesters reinforced with properly chosen nanofillers could potentially serve well as tailor-made PNCs for targeted applications.

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Section: Thermal Transitions and Calorimetric Polymersupporting

confidence: 88%

Molecular Dynamics in Nanocomposites Based on Renewable Poly(butylene 2,5-furan-dicarboxylate) In Situ Reinforced by Montmorillonite Nanoclays: Effects of Clay Modification, Crystallization, and Hydration

et al. 2020

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“…For the “dry state” measurements, the dominant relaxation times were slow and on the order of 10 ‐1 –10 ‐3 s with values of Δε ranging only from ~10 to 20. The origins of this low frequency dispersion is likely related to concentrated ions in the EDL with retarded motion (Saint‐Amant & Strangway, ) and small amounts of clay interlayer water (Vasilyeva et al, ).…”

Section: Resultsmentioning

confidence: 99%

Dielectric Polarization Studies in Partially Saturated Shale Cores

et al. 2019

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Dielectric measurements of reservoir rocks are used to estimate important petro-physical properties such as water-filled porosity and pore surface textures. However, complex dielectric polarization processes that occur in rocks are strongly dependent on frequency, making physically meaningful interpretation of broadband dielectric data difficult. At high frequency (> 10 MHz) dielectric permittivity primarily relates to the volume fractions of constituents (i.e., saturation, minerals), while at lower frequency (< 10 MHz), interpretation is complicated by interfacial polarization, electro-diffusion phenomena, and ohmic conduction. The ability to de-convolve these electrical processes is critical for interpreting petro-physical properties from broadband dielectric data. Here we demonstrate the application of Tikhonov regularization methods to compute dielectric relaxation time distributions from broadband (40 Hz to 110 MHz) dielectric data for ten shale core samples at varying partial saturation. Furthermore, via the Kramers-Kronig relation, the contribution from in-phase conduction currents to the imaginary component of the dielectric response was quantified. The evolution of dielectric polarization processes with increasing moisture content was analyzed directly from changes in relaxation time distributions. It was found that the dominant polarization mechanism, up to a critical partial saturation, occurred as surface polarization within the electrical double layer. Above this critical partial saturation, electro-diffusion mechanisms acting between the Stern and diffuse layers resulted in a large low frequency response. This work provides valuable insight into dielectric polarization mechanisms in shales and demonstrates such measurements are sensitive to electrical double layer properties and electro-diffusion length scales that are potentially relevant to characterizing pore-scale properties in shales. Key Points:• Tikhonov regularization methods were applied to compute dielectric relaxation time distributions from broadband dielectric data • Dielectric relaxation time distributions for a range of shale samples were determined as a function of water saturation • Above a critical partial saturation, electro-diffusion mechanisms dominated the low frequency dielectric permittivity

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“…Several previous studies have investigated the dynamics of nanotrapped water in C−S−H materials using different experimental techniques. Among these techniques, broadband dielectric spectroscopy (BDS) is a nondestructive experimental technique commonly used for the investigation of the dynamics of confined water, [14,15] in both biological systems, [16–18] and porous materials (such as clays, [19–22] molecular sieves, [23–26] and zeolites [27,28] ). In fact, due to its large frequency (10 −6 –10 12 Hz) and temperature (100–670 K) ranges, this technique allows us to explore the dynamic features of water over an extremely broad time range, from 10 2 to 10 −8 s [29] .…”

Section: Introductionmentioning

confidence: 99%

Correlation between the Dynamics of Nanoconfined Water and the Local Chemical Environment in Calcium Silicate Hydrate Nanominerals

Musumeci

Goracci

Camacho

et al. 2021

Chemistry A European J

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Calcium silicate hydrates are members of a large family of minerals with layered structures containing pendant CaOH and SiOH groups that interact with confined water molecules. To rationalize the impact of the local chemical environment on the dynamics of water, SiOH‐ and CaOH‐rich model nanocrystals were synthesized by using the continuous supercritical hydrothermal method and then systematically studied by a combination of spectroscopic techniques. In our comprehensive analysis, the ultrafast relaxation dynamics of hanging hydroxy groups can be univocally assigned to CaOH or SiOH environments, and the local chemical environment largely affects the H‐bond network of the solvation water. Interestingly, the ordered “ice‐like” solvation water found in the SiOH‐rich environments is converted to a disordered “liquid‐like” distribution in the CaOH‐rich environment. This refined picture of the dynamics of confined water and hydroxy groups in calcium silicate hydrates can also be applied to other water‐containing materials, with a significant impact in many fields of materials science.

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Dielectric Relaxation of Water in Clay Minerals

Cited by 42 publications

References 42 publications

Molecular Dynamics in Nanocomposites Based on Renewable Poly(butylene 2,5-furan-dicarboxylate) In Situ Reinforced by Montmorillonite Nanoclays: Effects of Clay Modification, Crystallization, and Hydration

Molecular Dynamics in Nanocomposites Based on Renewable Poly(butylene 2,5-furan-dicarboxylate) In Situ Reinforced by Montmorillonite Nanoclays: Effects of Clay Modification, Crystallization, and Hydration

Dielectric Polarization Studies in Partially Saturated Shale Cores

Correlation between the Dynamics of Nanoconfined Water and the Local Chemical Environment in Calcium Silicate Hydrate Nanominerals

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