Permittivity Of Liquids Research Articles

Mixed finite element analysis for a modified Poisson–Fermi interface problem accounting for electrostatic correlations

The Bazant–Storey–Kornyshev (BSK) theory [1–3] recently developed an important continuum framework to expound the nonlocal dielectric permittivity of ionic liquids due to electrostatic correlations, leading to a fourth-order modified Poisson–Fermi equation to model the electrostatic potential field in the solvent (e.g., the electrolyte), while the standard second-order Poisson–Fermi equation is still valid in modeling the electrostatic potential field in the solute. Thus an interface problem is formed between the fourth-order and second-order Poisson–Fermi equations through the interface of solvent and solute with jump coefficients, which has exerted tremendous impacts on applications of electrokinetics, electrochemistry, biophysics, and etc. In this paper, a type of mixed finite element method is developed to solve the proposed interface problem once for all variables: the electrostatic potential, electric field, electric displacement field, electrostatic stress as well as interactional force in the electrolyte in an accurate fashion, and its optimal convergence properties are analyzed for all variables in their respective norms. Numerical experiments are carried out through self-defined mathematical examples to validate all attained theoretical results. Furthermore, as a part of modeling verification for the presented interface problem that models the BSK theory, a practically physical example is investigated to validate the necessity of introducing the fourth-order modified Poisson–Fermi equation to describe the electrostatic correlation effects due to charge reversal phenomenon.

Molecular modeling and simulation of organic electrolyte solutions for lithium ion batteries.

Multi-criteria optimization is used for developing molecular models for ethylene carbonate (EC) and propylene carbonate (PC), organic solvents commonly used in Li-ion batteries. The molecular geometry and partial charges of the solvents are obtained from quantum mechanical calculations. Using a novel optimization strategy that combines systematic variations of the Lennard-Jones parameters with a reduced units approach, the models are fitted to experimental data on the liquid density, vapor pressure, relative permittivity, and self-diffusion coefficient. Since no experimental data for the self-diffusion coefficient of pure EC were available in the literature, they are measured in this work using a gradient-based nuclear magnetic resonance technique. For all pure component properties, excellent agreement between experiment and simulation is obtained. Moreover, the predictive capabilities of the new solvent models are assessed by comparison to experimental data for the liquid density and relative permittivity of mixtures of EC and PC. In addition, molecular models for the anions PF6-, BF4-, and ClO4- in solutions of their lithium electrolytes in PC are developed using experimental data on the solution densities. Finally, the self-diffusion coefficients of LiPF6 in PC and in aqueous solution are predicted and compared, showing that diffusion is much slower in the organic solution due to the formation of larger solvent shells around the ions. Furthermore, an analysis of the radial distribution functions in these solutions suggests that the ions have much less impact on the structure of the solvent PC than on water.

High-Sensitivity Differential Sensor for Characterizing Complex Permittivity of Liquids Based on LC Resonators.

This paper proposes a high-sensitivity microstrip differential sensor for measuring the complex permittivity of liquids. The prototype of the differential sensor was formed by cascading two LC resonators on a microstrip transmission line based on stepped impedance. A strong electric field was found to be distributed in the circular patch of the LC resonator; therefore, a cylindrical micropore was set in the center of the circular LC resonator to measure the dielectric sample, which maximized the disturbance of the dielectric sample on the sensor. By optimizing the size of the circular LC resonator, a high-sensitivity sensor circuit was designed and manufactured. The complex permittivity of the test sample was calculated by measuring the transmission coefficient of different molar concentrations of ethanol-water solutions. The experimental results show that the designed differential sensor can accurately measure the complex permittivity of liquid materials with an average sensitivity of 0.76%.

High sensitivity metasurface sensor for estimating the complex permittivity of ionic liquids

In this paper, a sensor based on a metasurface structure for the complex permittivity of ionic liquids is designed. The structure consists of an F4B substrate with a metal resonance pattern, and a polystyrene foam box is used to contain the ionic liquids to achieve non-contact measurements. The simulation results show that without the presence of the ionic liquids, the sensor can achieve a significant reflection spectrum depth of −37 dB at 11.2 GHz, after adding the ionic liquids, the sensor can generate different responses depending on the types of ionic liquids in the frequency range of 8–9.3 GHz. Furthermore, by employing a characteristic matrix model inversion based on the relationships between the complex permittivity, resonance frequency, and quality factor variations, the standard deviations of the real and imaginary parts of the complex permittivity for seven ionic liquids are estimated to be 0.18 and 0.3, respectively. The estimated results show a good agreement with the standard values obtained from probe measurements. The sensor designed in this paper features a small size, simple structure, and low fabrication cost. With a volume of 0.216 milliliters of the sample, it achieves a high sensitivity of 462.87 MHz/ԑ′and frequency detection resolution of 391.57 MHz/ԑ′. It demonstrates excellent discriminatory detection capability for ionic liquids, providing a new direction for the application research of metasurfaces.

A Novel Substrate Integrated Waveguide Shorted Coaxial Resonator for Characterizing Complex Permittivity of Liquids and Solid Content of Water-Based Ferrofluid

A Novel Substrate Integrated Waveguide Shorted Coaxial Resonator for Characterizing Complex Permittivity of Liquids and Solid Content of Water-Based Ferrofluid

Density dependence for the dielectric permittivity of simple gases and liquids

The present work is devoted to the analysis of polarization effects in atomic systems of the argon type. Special attention is given to the manifestation of the polarizabilities of two particles in the density dependence of the dielectric permittivity of a system and its effective molecular polarizability. It is shown that the effective polarizability of a molecule in the liquid state of a system is mainly caused by deviation of the molecular distribution in the first coordination layer from the spherical one. Due to this, the atomic polarizability inherent to rarefied gas increases practically twice near the triple point. The interconnection between the atomic polarizability and the proper volume of an atom is discussed in detail. It is established that the optimal size of an atom follows from the kinematic shear viscosity measurements.

Moisture measuring antenna promises a bounty of potential for farmers

Slot modifications in microstrip patch shown to significantly enhance liquid permittivity sensing

Effect of charge on the rotation of prolate nitroxide spin probes in room-temperature ionic liquids

We have studied the rotational diffusion of two prolate nitroxide probes, the doubly negatively charged peroxylamine disulfonate (Frémy's salt − FS) and neutral di-tert-butyl nitroxide (DTBN), in a series of 1-alkyl-3-methylimidazolium tetrafluoroborate room-temperature ionic liquids (RTILs) having alkyl chain lengths from two to eight carbons using electron paramagnetic resonance (EPR) spectroscopy. Though the size and shape of the probes are reasonably similar, they behave differently due to the charge difference. The rotation of FS is anisotropic, and the rotational anisotropy increases with the alkyl chain length of the cation, while the rotation of DTBN is isotropic. The hyperfine coupling constant of DTBN decreases as a function of the alkyl chain length and is proportional to the relative permittivity of ionic liquids. On the other hand, the hyperfine coupling constant of FS increases with increasing chain length. These behaviors indicate the location of each probe in RTILs. FS is likely located in the polar region near the network of charged imidazolium ions. DTBN molecules are predominately distributed in the nonpolar domains.

Microwave Differential CSRR Sensor for Liquid Permittivity Measurement

Microwave Differential CSRR Sensor for Liquid Permittivity Measurement

Determining the Permittivity of a High-Loss Liquid by Resonant Method in Ka-Waveband

Determining the Permittivity of a High-Loss Liquid by Resonant Method in Ka-Waveband

A Microfluidic Antenna-Sensor for Contactless Characterization of Complex Permittivity of Liquids

A Microfluidic Antenna-Sensor for Contactless Characterization of Complex Permittivity of Liquids

New Radio-Frequency Liquid Permittivity Measurement System Using Filter-Based Microfluidic Sensor

A new radio-frequency (RF) liquid permittivity measurement system using a filter-based microfluidic sensor is proposed in this paper. Integrating the filter-based sensor with an RF source, a power divider, and a gain/phase detector can form a new permittivity measurement system without using a bulky and expensive vector network analyzer (VNA) to acquire measured data. Since two coupled resonators with a strong coupling synthesize the filter-based sensor, it can provide a stronger electric-field concentration in the sensing area and improve the sensor’s sensitivity. The 8-μL water-ethanol mixtures with ethanol volume fractions (EVF) ranging from 10% - 90% in 10% increments are used as the test liquids to evaluate the proposed sensor and system. Compared with the measured results using the commercial dielectric probe kit, the maximum errors of ε′ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> and ε″ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> using the filter-based sensor with a VNA are -4.34% and 13.24%, respectively. At the same time, ε′ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> and ε′ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> errors are 8.28% and 14%, respectively, using the proposed permittivity measurement system. Since the proposed permittivity measurement system can flexibly synthesize the sensing area size, control the electric-field intensity, and get rid of a VNA, it makes it easier to satisfy the requirements of various microfluidic sensing scenarios.

Meniscus-Corrected Method for Broadband Liquid Permittivity Measurements with an Uncalibrated Vector Network Analyzer

We present a novel broadband permittivity characterization method for liquids measured in a semi-open vertically oriented test cell with an uncalibrated vector network analyzer. For this goal, we utilize three scattering matrices measured at different levels of liquid in the cell. With mathematical operations, we remove the effects of systematic measurement errors caused by both the vector network analyzer and a meniscus shaping the top of the liquid samples in such a type of test cell. To the best authors’ knowledge, this is the first of such a calibration-independent method dealing with meniscus. We verify its validity by comparing our results with the data available in the literature and with the outcomes of our previously published calibration-dependent meniscus removal method (MR) for propan-2-ol (IPA), a 50% aqueous solution of IPA and distilled water. The new method yields results comparable with the MR method, at least for IPA and the IPA solution, revealing, however some problems when testing high-loss water samples. Nevertheless, it allows one to cut down on expenditures in the system calibration engaging skilled labor and expensive standards.

Magnetic and ionic liquid inclusions in soft materials and engineering enhanced electro-magneto-mechanical response

Magnetoelectric soft materials that polarize in the existence of external magnetic field and magnetize in response to an applied electric voltage have several promising technological applications. However, finding the suitable candidate for device fabrication has been a challenging task. Previous experiments and numerical modeling suggested an enhanced electrostrictive properties for soft materials composites made by depositing high permittivity liquid inclusions. Similarly, it has been reported that small magnetic inclusions significantly improve the magnetostrictive response of a soft composite. In this work, we highlight a simple yet effective mechanism to design soft materials composites with unusually large magnetoelectric coupling, merely by adding minute spherical liquid inclusions. Using a simple homogenization model, we explore the interplay of electrostatics, magnetostatics, soft solids and liquid inclusions on the effective coupling behavior of the soft composite while properly accounting for the capillary effects. This soft composite, which naturally allows large deformations, is also capable of generating electric voltage when subject to an external magnetic field. Meticulous selection of the size of liquid or solid inclusions, volume fraction and matrix materials properties significantly impacts the magnetoelectric coupling coefficient of the soft composite. In particular, choosing ferrofluids improves magnetoelectric response by 134% or higher. Moreover, in the absence of an electric field, a stronger magnetostrictive effect is revealed by ionic liquid inclusions compared to stiff ones, even in the presence of an applied mechanical strain.

Ionic Signal Amplification of DNA in a Nanopore (Small Methods 11/2022)

Back Cover In article number 2200761, Tsutsui, Kawai, and co-workers demonstrated ionic signal amplifications of single-molecule DNA in a nanopore by applying a liquid permittivity gradient across membranes. This simple method can boost the ability of nanopore sensing to readout genome sequences at the single-molecule level.

3D Printed Platform for Impedimetric Sensing of Liquids and Microfluidic Channels.

Fused deposition modeling 3D printing (FDM-3DP) employing electrically conductive filaments has recently been recognized as an exceptionally attractive tool for the manufacture of sensing devices. However, capabilities of 3DP electrodes to measure electric properties of materials have not yet been explored. To bridge this gap, we employ bimaterial FDM-3DP combining electrically conductive and insulating filaments to build an integrated platform for sensing conductivity and permittivity of liquids by impedance measurements. The functionality of the device is demonstrated by measuring conductivity of aqueous potassium chloride solution and bottled water samples and permittivity of water, ethanol, and their mixtures. We further implement an original idea of applying impedance measurements to investigate dimensions of 3DP channels as base structures of microfluidic devices, complemented by their optical microscopic analysis. We demonstrate that FDM-3DP allows the manufacture of microchannels of width down to 80 μm.

Ionic Signal Amplification of DNA in a Nanopore.

Ionic signal amplification is a key challenge for single-molecule analyses by solid-state nanopore sensing. Here, a permittivity gradient approach for amplifying ionic blockade characteristics of DNA in a nanofluidic channel is reported. The transmembrane ionic current response is found to change substantially through modifying the liquid permittivity at one side of a pore with an organic solvent. Imposing positive liquid permittivity gradients with respect to the direction of DNA electrophoresis, this study observes the resistive ionic signals to become larger due to the varying contributions of molecular counterions. On the contrary, negative gradients render adverse effects causing conductive ionic current pulses upon polynucleotide translocations. Most importantly, both the positive and negative gradients are demonstrated to be capable of amplifying the ionic signals by an order of magnitude with a 1.3-fold difference in the transmembrane liquid dielectric constants. This phenomenon allows a novel way to enhance the single-molecule sensitivity of nanopore sensing that may be useful in analyzing secondary structures and genome sequence of DNA by ionic current measurements.

Measurement of complex permittivity of liquids in the frequency range 100-1000MHz by using a re-entrant cavity.

For many liquid materials and biological media, their complex permittivity varies with frequency in the P-band (100-1000MHz). In this paper, a re-entrant coaxial cavity resonance test system with intensive multi-frequency points testing capability is designed for the P-band to realize the test of the complex permittivity of P-band materials. For this system, a test algorithm has been written, and on the basis of this system, a perturbation block has been designed, using stepper motors to control the up and down movement of the perturbation block to achieve frequency tunability of the cavity, enabling more P-band frequency test data to be obtained. The experimental results show that the system is suitable for testing the electrical parameters of P-band biological media and liquid materials and for testing solid materials in aerospace, electromagnetic shielding, and other fields where there is a great demand for P-band testing.

A compact repetitive high energy-density accelerator HEART-20 based on propylene carbonate pulse forming line.

The development of pulsed power technology requires an electron beam accelerator with high output power and repetitive operation. A compact repetitive electron beam accelerator based on a pulse transformer and a pulse forming line of high permittivity liquid, as an essential type of one, has attracted extensive attention at the present time. In this paper, the development of a compact high energy-density electron beam accelerator, viz., HEART-20, based on a propylene carbonate (PC) forming line is presented. The accelerator HEART-20 consists of a primary energy source, a pulse transformer, a PC pulse forming line, a gas spark gap switch, and a vacuum diode. First, the operation principle of the accelerator is described. Second, the design of the accelerator's parameters is presented. A pulse transformer is developed for rapid charging of the PC-filled pulse forming line. The coupling coefficient is above 0.9, the voltage ratio is about 200, and the operation voltage is about 800kV. Third, the energy storage characteristics of PC are investigated. The insulation characteristics of PC under positive charging voltage are found to perform better than those under negative charging voltage. The insulating strength of PC can be improved by pressurization. Finally, the development of the accelerator HEART-20 is presented. Across a vacuum diode load, it can steadily operate at a 20 GW output power in 5Hz rep-rate. Moreover, it can drive a magnetically insulated line oscillator to produce about 2.0 GW microwave. These findings provide a good foundation for the development of a rep-rate intensive electron beam accelerator with promising applications for the future.

Coaxial resonant cavity for measuring complex permittivity of liquids

Abstract In this letter, a new microwave sensor of the coaxial resonant cavity with a single-open-ended circuit loaded capacitor is proposed and used to detect the liquids’ complex permittivity. The improved cavity has a higher internal electric field and smaller size when compared with the cylindrical cavity, which gives the sensor a high sensitivity in measuring liquids’ complex permittivity. A coaxial resonant cavity operating in 1.9 GHz was designed in this work. The silicone hose used for the test is inserted vertically from the center of the cavity, and the liquids under test (LUTs) are guaranteed to be 2 ml each time. The dielectric properties of LUTs will cause perturbation to the internal electric field of the cavity. By analyzing the measured data, the sensitivity of the cavity is 0.12%, and the relative errors of the real part of the measured value and the reference value are 3.67%. which shows the measured value has a good agreement with the reference value.