Dielectric Constant Research Articles

Dielectric Properties of Water with a Low Quantity of NaCl inside Charged Nanoslits.

A 0.5 molal solution of NaCl in water confined within charged graphene nanoslits represents an intriguing system for molecular dynamics simulation, functioning as a model for a nanocapacitor. This charged configuration not only holds practical significance for the advancement of nanoscale capacitors but also offers valuable insights into how the charged walls and applied electric field influence the structure of water, the movement of ions within the solution, and how these alterations in water impact the overall fluid behavior. The behavior of the solution under nanoconfinement diverges markedly from that observed in bulk conditions, exhibiting distinct structural, dynamic, and dielectric properties. The charging of the graphene nanoslits generates an electric field within the nanopore, which plays a critical role in modulating molecular interactions. Key properties, including the static dielectric constant, polarization, and density of the 0.5 molal solution, are systematically examined through the molecular structure of the confined system. The models employed in this study include the flexible FAB/ϵ model of water, which effectively reproduces various experimental properties of water under different pressure and temperature conditions. Additionally, the NaCl/ϵ model is used, which also captures a range of experimental characteristics associated with sodium chloride solutions. Together, these models facilitate a comprehensive understanding of the complex behavior of water and ions under the influence of nanoconfinement and electric fields, providing insights that are essential for both fundamental science and practical applications in nanotechnology.

Analysis of cell characteristics depending on vertical channel profile and multiple dielectric WL space in 3D NAND flash memory

Abstract Convex and concave channel structures are formed due to the increase in the number of layers of 3D NAND flash, along with the limitations of the technology to etch holes in the channel. The program, interference, retention characteristics of convex and concave structures are investigated. The program and interference characteristics are improved in the convex structure due to the concentrated E-field in the word line. The retention characteristics are improved in the concave structure due to the dispersed E-field. In addition, various space materials are considered to confirm cell characteristics according to the dielectric constant, and it was found that these characteristics are improved when air space is used.

Experimental investigation on the reverse mechano-electrical effect of porcine articular cartilage

IntroductionThe electric signals within the cartilage tissue are essential to biological systems and play a significant role in cartilage regeneration. Therefore, this study analyzed and investigated the reverse mechano-electrical effect in porcine articular cartilage and its related influencing factors.MethodsThe deflection of cartilage samples in an electric field was measured to analyze the mechanisms of different factors affecting the reverse mechano-electrical effect in articular cartilage.ResultsThe results showed that the cartilage thickness, water content, and externally applied voltage all impacted the deflection of the cartilage. The reduction in cartilage water content resulted in a decrease in cartilage thickness, following the same influencing mechanism as thickness. On the other hand, an increase in the externally applied voltage led to an increase in the electric field force within the cartilage space, consequently increasing the deflection of the cartilage in the electric field. Additionally, the externally applied voltage also caused a slight temperature rise in the vicinity of the cartilage specimens, and the magnitude of the temperature increase was proportional to the externally applied voltage.DiscussionThe fitting results of the experimental data indicated that cartilage thickness influenced the dielectric constant and moment of inertia of the cartilage in the electric field, thereby affecting the magnitude of the electric field force and deflection of the cartilage. This may provide valuable insights for further investigation into the microscopic mechanisms of cell proliferation, differentiation, and cartilage regeneration induced by electrical stimulation.

Dielectric Regulation in Quasi-vdW Europium Oxysulfur Compounds by Compositional Engineering for 2D Electronics.

Advancing next-generation electronics necessitates precise control of dielectric properties in 2D materials. Here, the first synthesis of novel 2D quasi-van der Waals (vdW) europium oxysulfur (Eu2SOx) compounds, comprising hexagonal Eu₂SO₂ and tetragonal Eu₂SO₆ phases, with composition-tunable dielectric properties, is presented. Using a homodiffusive-controlled epitaxial growth method, materials are achieved with complementary characteristics: the hexagonal Eu₂SO₂ phase exhibits a high dielectric constant (≈30) paired with a moderate bandgap (≈4.56 eV), while the tetragonal Eu₂SO₆ phase offers a wider bandgap (≈5.62 eV) but a lower dielectric constant (≈20). The potential of these materials is demonstrated by integrating ultrathin Eu₂SO₂ nanoplates with molybdenum disulfide (MoS₂) field-effect transistors (FETs) via vdW forces. The resulting devices achieve a near-ideal Ion/Ioff ratio (≈10⁸), minimal hysteresis (≈5.3 mV), a low subthreshold slope (≈63.5 mV dec⁻¹), and ultralow leakage current (≈10⁻¹⁴ A). These results highlight the capacity of europium oxysulfur compounds to address the trade-off between dielectric constant and bandgap, offering tailored solutions for diverse 2D electronic applications. This work underscores the potential of composition engineering to expand the family of rare-earth oxysulfur compounds for nanoelectronics, paving the way for innovative gate dielectrics in next-generation devices.

Broadband Rectangular Microstrip Antenna with Slits for W-Band Applications

This work introduces a broadband rectangular patch antenna optimized for efficient data transmission in the W-band, particularly for 5G applications. By integrating two I-shaped slits with the radiating element, the antenna achieves an impressive performance, exhibiting wide bandwidth and excellent radiation characteristics. Utilizing Rogers RT5880 as the substrate material with a relative permittivity (εr) of 2.2, a small antenna with a size of 3.7 × 4.1 × 0.16 mm³ is realized. Extensive simulations are conducted using CST software in both frequency and time domains to optimize the antenna. The results show a notable 16% fractional bandwidth from 80.75 GHz to 94.79 GHz, with dual resonance frequencies at 84.5 GHz and 91.5 GHz, primarily a result of the incorporated slits. At 84.5 GHz, the antenna demonstrates an outstanding reflection coefficient of -66.37 dB, a Voltage Sanding Wave Ratio (VSWR) of 1.00096, a gain of 9.71 dBi, a directivity of 9.75 dB, and a high radiation efficiency of 91.8%. Similar trends are observed at 91.5 GHz, where the return loss remains at an impressive value of 55.92 dB and the VSWR maintains a very low value of 1.0032, indicating continued excellent impedance matching. While the gain (6.98 dBi) and directivity (7.05 dB) are slightly lower at this frequency, the radiation efficiency remains remarkably high at 94.9%, indicating efficient energy utilization. The wide bandwidth of the proposed design enables high data transfer rates, a crucial requirement for 5G networks. This translates to significant improvements in network capacity, allowing for more connected devices and data traffic. Additionally, the design exhibits excellent signal transmission characteristics, ensuring reliable data transfer. Finally, the antenna's compact size and efficient radiation have the potential to reduce power consumption in 5G devices, contributing to improved battery life and sustainability.

In-vitro testing and circuit analysis of an ultra-miniaturized biosensor for multiple medical implant systems

This paper presents an ultra-miniaturized and flexible biosensor for multiple medical implant systems, operating in the 2.4 GHz Industrial, Scientific, and Medical (ISM) band. A flexible Rogers RO Duroid 3010 material with a dielectric constant (εr) 10.2, loss tangent (δ) 0.0022 and thickness of 0.635 mm is utilised as a substrate and superstrate for the proposed biosensor. The size of an biosensor is 10 mm × 10 mm. Certain design elements are employed to accomplish a miniaturized geometry, such as a slotted radiating patch and ground plane, a flexible substrate and superstrate material. A realistic simulation environment has been utilized to evaluate the performance of the proposed biosensor in multiple tissues, encompassing both homogeneous and heterogeneous situations within different organs. This enables the examination and advancement of the practicality of several implantable applications. The proposed biosensor is validated by making an equivalent circuit. The biosensor exhibits a higher gain of −13.18 dB and a higher bandwidth of 16.52 % at the desired ISM band. To test the practicality of a proposed biosensor, in-vitro measurements have been carried out using different tissue-mimicking phantoms. Moreover, a proposed biosensor’s specific absorption rate (SAR) in multiple tissues has also been calculated. The proposed biosensor demonstrates a good correlation between simulated and measured results, which makes the biosensor an excellent choice for implantation inside multiple medical implant devices.

Influence of Alkyl Chain Length and Bromine Substitution on Thermal, Photophysical, and Optical Properties of Biphenyl Luminescent Molecules

This study investigates a series of bromine-substituted alkoxy biphenyl derivatives to explore their potential as luminescent and optical materials for applications in display technologies, sensors, and photonic devices. Four compounds were synthesized, including 5-Br, 6-Br, 7-Br, and a comparative non-halogenated molecule 6-H. The findings reveal that the bromine-substituted derivatives exhibit enhanced thermal stability as the alkoxy chain length increases, though none of the compounds displayed liquid crystalline phases, likely due to molecular flexibility and steric hindrance from the bromine atoms. Photophysical studies showed that the compounds exhibit tunable emission colors ranging from green to blue, depending on the side chain length and the presence or absence of bromine. Importantly, the introduction of bromine was found to enhance the photophysical properties, including increased quantum yields and longer emission lifetimes, compared to the non-halogenated analog. Moreover, these luminescent molecules can maintain strong fluorescence both in solution and when forming aggregates. Furthermore, the optical properties, such as dielectric constant, extinction coefficient, refractive index, and optical conductivity, were thoroughly examined. The results indicate that structural variations, including alkyl chain length and bromine substitution, significantly influence the capability of these materials to store and dissipate electrical energy. Their strong optical responses, high energy storage capabilities, and sensitivity to structural modifications suggest that the studied materials have substantial potential for applications in energy storage, sensing, optoelectronics, and non-linear optics. These findings offer important guidelines for the rational design of multifunctional luminescent and optical materials, representing a significant step forward in the development of practical applications of smart materials and advanced photonic devices.

Preparation of modified epoxy resin with high hydrophobicity, low dielectric constant, toughness, and flame retardant by epoxy-functionalized siloxanes

A series of α, ω-dimethylglycidoxypropyl-terminated PDMS oligomer (PDMS-GE) oligomers with different polymerization degrees were synthesized and used to modify the bisphenol-A diglycidyl ether E51 (DGEBA) / 4,4-diaminodiphenylmethane (DDM) epoxy resin, resulting in epoxy resins with high hydrophobicity, low dielectric constant, good impact toughness, low combustion heat release rate, and low total heat release. The combustion heat release rate and total heat release of the material decreased with the increase in the loadings of PDMS-GE. Relative to pure epoxy resin, the composite E51/D30–10, which using DGEBA as the matrix, PDMS-GE with a degree of polymerization of 30 as the modifier in an amount of 10 phr relative to the mass sum of DGEBA, PDMS-GE and DDM, exhibited the best comprehensive performance with a water contact angle of 102.42°, a dielectric strength of 6.49 kV/mm, a dielectric constant of 2.93 at 14.2 GHz, the peak rate of heat release (PRHR) and total heat release (THR) are of 378.3 kW/m2 and 134.4 MJ/m2, respectively. These comprehensive performances underscore the potential of PDMS-GE oligomers in significantly improving epoxy resin properties. When the loadings of PDMS-GE oligomers are less than 5 wt%, PDMS-GE with a lower degree of polymerization can improve the toughness of epoxy resins. The impact strength of the composite E51/D24–5, which uses DGEBA as the matrix, PDMS-GE with a degree of polymerization of 24 as the modifier in an amount of 5 phr relative to the mass sum of DGEBA, PDMS-GE, and DDM, reaches 98.1 kJ/m2, which is about 28.9 % higher than that of pure epoxy resin. The results also indicated that the degree of polymerization of PDMS-GE oligomers has less influence on the dielectric properties and mechanical properties of composite materials.

A Comparative Study Between Micro and Millimeter Impedance Sensor Designs for Type-2 Diabetes Detection

In recent years, various types of sensors have been developed at both millimeter (mm) and micrometer (µm) scales for numerous biomedical applications. Each design has its own advantages and limitations. This study compares the electrical characteristics and sensitivity of millimeter- and micrometer-scale sensors, emphasizing the superior performance of millimeter-scale designs for detecting type-2 diabetes. Elevated glucose levels in type-2 diabetes alter the complex permittivity of red blood cells (RBCs), affecting their rheological and electrical properties, such as viscosity, volume, relative permittivity, dielectric loss, and AC conductivity. These alterations may manifest as a unique bio-impedance signature, offering a diagnostic topology for diabetes. In view of this, various concentrations (ranging from 10% to 100%) of 400 µL of normal and diabetic RBCs suspended in phosphate-buffered saline (PBS) solution are examined to record the changes in bio-impedance signatures across a spectrum of frequencies, ranging from 1 MHz to 10 MHz. In this study, simulations are performed using the finite element method (FEM) with COMSOL Multiphysics® to analyze the electrical behavior of the sensors at both millimeter (mm) and micrometer (µm) scales. These simulations provide valuable insights into the performance parameters of the sensors, aiding in the selection of the most effective design by using this topology.

Boosting dielectric constant of laminated composites by involving an epsilon-negative layer

Boosting dielectric constant of laminated composites by involving an epsilon-negative layer

Microstructural study with enhanced dielectric and magnetic properties of M−type Nd doped Ba1-xNdxFe12O19 (x = 0–0.20) hexaferrites synthesized via sol–gel auto-combustion route

In the present study, we have examined the influence of Nd doping on the structural, morphological, magnetic, and dielectric properties of barium hexaferrite (Ba1-xNdxFe12O19; 0 ≤ x ≤ 0.20) samples synthesized via the sol–gel auto-combustion route. The XRD patterns confirm the formation of the hexagonal phase, in addition to minor traces of Fe2O3 impurity in the samples. Doping with Nd3+ ions produced strain in the crystal, and the samples retain their hexagonal phase with space group P63/mmc, as ensured by the Rietveld refinement method. FTIR spectroscopy were performed for microstructural analysis, which shows the corresponding stretching and bending bands of iron and oxygen in the samples. The Raman spectra confirmed the Raman fundamental modes at various wavenumbers, which also confirm the hexagonal structure of the samples. The electronic states of all metal ions state were confirmed through x-ray photoelectron (XPS) spectroscopy analysis, which show that iron is present in two oxidation states (Fe2+ and Fe3+) in all the prepared samples. XPS spectra also revealed that the Nd-doped sample is more defective as compared to pure sample. Scanning electron microscopy (SEM) micrographs shows that the non-uniform particle size in the nanometer range. Elemental composition is confirmed using energy dispersive x-ray spectroscopy (EDS) measurement. Additionally, magnetic measurements using a vibrating sample magnetometer (VSM) revealed that the hysteresis loops for 5 % Nd-doped sample shows the maximum value 44.3 emu/g of magnetization, and its values decrease for further increase in Nd doping concentration. The dielectric measurements were performed at room temperature in the frequency range of 1 Hz to 10 MHz, when Nd3+ is doped at the Ba site, it enhances the dielectric constant, dielectric loss, tangent loss, and ac conductivity of the synthesized samples.

Physical properties of ultrasonic assisted MWCNT/Ni0.5Co0.5Pr0.2Fe1.8O4 nanocomposites for future energy storage applications

The demand for materials with superior magnetic and dielectric properties is critical for the advancement of high-performance electronic and magnetic devices. In response to this need, Ni0.5Co0.5Pr0.2Fe1.8O4 (NiCoPrFeO) nanoparticles were synthesized using the sol–gel auto-combustion technique, known for its simplicity and versatility. To enhance the functional properties of these nanoparticles, multiwalled carbon nanotubes (MWCNTs) were incorporated, recognized for their high electrical conductivity and low density, to create a novel nanocomposite. The structural and physical properties of the prepared NiCoPrFeO/MWCNTs nanocomposites were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), and Impedance Analysis. XRD confirmed the successful formation of the nanocomposite NiCoPrFeO/MWCNTs. TEM provided detailed insights into particle size to be around 18.553 and the interactions between the nanoparticles and MWCNTs. FTIR spectra indicated the presence of absorption bands ‘ν1′ and ‘ν2′ to be around 545 and 415 cm−1 which is characteristic of the cubic spinel structure. The addition of MWCNTs significantly improved the magnetic properties of the nanocomposite, with higher MWCNT concentrations leading to stronger magnetization, as shown by VSM analysis the values of Mr, Ms and Hc were found between 1.41 to 4.79 emu/g, 16.67 to 24.35 emu/g and 204.29 to 569.77 Oe, respectively. The dielectric properties, including dielectric constant, dielectric loss, loss tangent, and AC conductivity, exhibited notable improvements with increasing MWCNT content across varying frequencies. These results suggest that NiCoPrFeO/MWCNTs nanocomposites could be a promising solution for improving materials used in electronic and magnetic devices, leading to more efficient and advanced technologies.

High dielectric energy storage properties of chitin matrix composites regulated by SiO2.

High-performance polymer-based dielectric materials have attracted much attention in the field of energy storage due to high breakdown field strength and low cost. However, partial polymer-based materials are derived from traditional fossil energy derivatives, which are characterized by non-renewable and low dielectric constants, which are not conducive to the improvement of energy storage. In this paper, dissolved chitin through alkali/urea system is composited with SiO2 prepared by electrostatic spinning. The maximum discharge energy density of the fiber composite film reaches 4.34Jcm-3, which is 1.6 times higher than that of the micron particle composite film (2.8Jcm-3) and 1.9 times higher than that of the pure chitin film. The high aspect ratio and low concentration of silica filler effectively improved the breakdown field strength. In addition, the thermal stability was improved. This study paves the way for the application of bio-based materials in high-performance dielectrics.

Advanced Study of Structural and Optical Characteristics of Nanocrystalline Coomassie Brilliant Blue G-250 for Optoelectronic Device Optimization

This study explores the structural and optical properties of Coomassie Brilliant Blue G-250 (CBBG) using X-ray diffraction (XRD) and spectroscopic techniques. XRD analysis of both powder and thin film samples reveals distinct structural features: the powder exhibits a polycrystalline structure with strong diffraction peaks corresponding to cubic lattice planes, while the thin film shows a mix of crystalline orientations within an amorphous matrix. The Williamson-Hall relation is applied to determine average crystallite sizes, yielding 85.5nm for the powder and 71.8nm for the thin film, indicating their nanocrystalline nature. Microstrain analysis also reveals compressive strain within the thin film. These structural insights are critical for understanding CBBG's mechanical and optical properties, vital for biochemical and optoelectronic applications. Density functional theory (DFT) calculations with the B3LYP/6-311++G(d,p) basis set were used to optimize the molecular geometry and analyze HOMO-LUMO energies and reactive sites via the MEP map. CBBG shows higher hyperpolarizability than urea, indicating its potential for nonlinear optical applications. Miller indices further support its optoelectronic optimization. The real (ε1) and imaginary (ε2) parts of the dielectric constant were analyzed, revealing CBBG thin films exhibit strong polarization and charge displacement, influenced by structural disorder. Additionally, the volume and surface energy loss functions (VELF and SELF) highlight significant internal energy dissipation, emphasizing CBBG's potential for optoelectronic devices. The complex optical conductivity analysis reveals key absorption and dispersion behaviors essential for advanced photonic and electronic device design.

Gas hydrate conditions prediction in the presence of salts by considering modified relative permittivity of solution; Application of the Kirkwood-Onsager approach

Gas hydrate conditions prediction in the presence of salts by considering modified relative permittivity of solution; Application of the Kirkwood-Onsager approach

High-Dielectric 2D Bismuth Oxides with Large Bandgaps: The Role of 6s2 Lone Pair Hybridization.

Large-bandgap and high-dielectric 2D dielectrics are crucial for transistor performance because they maximize gate-to-channel capacitive coupling, yet such high-quality materials remain scarce. This study employed first-principles calculations to predict 18 distinct 2D bismuth oxides (BiOs). It is demonstrated that the 6s2 lone pairs in 2D BiOs form benign positive feedback between the bandgap and dielectric constant. The hybridization of 6s2 and 6pz orbitals is key to setting the bandgap, revealing a significant negative linear relationship between the bond length and energy gap. In particular, due to the stereochemical activity of 6s2 that enhances the ionic contribution, these materials are capable of sustaining a high dielectric constant value surpassing 24, even within bandgaps wider than 4 eV. This discovery enhances the theoretical understanding of 2D materials exhibiting large bandgaps and high dielectric constants, providing deeper insights into the impact of lone pairs on 2D materials.

Impact of Electrical Properties Variations of Human-Body Phantom on Implantable Antenna Performance During In-Vitro Measurement

The Implantable Medical Antenna (IMA) is extensively used for continuous patient health monitoring. For in-vitro testing of IMA, the development of human-body-phantom is a necessary task before implantation within the torso. The phantom can be developed by mixing different chemicals. Evaporation from liquid phantom and bacterial activities in semi-solid phantom during in-vitro measurement can change the electrical properties (relative permittivity and conductivity) of the phantom model which may lead to variation in implantable antenna performance. From a realistic point of view, the overall permittivity and conductivity of the human body can change due to variations in water content, blood properties, collagen content, hormones, development of diseases especially cancer, Madelung’s disease, etc. Therefore, it is required to have knowledge about the dependence of IMA performance on equivalent electrical properties of homogeneous body phantom which has been studied in this article. From this study, it is observed using a curve-fitting technique that mathematical formulation between IMA parameters and variable effective permittivity and conductivity of equivalent body model are difficult. That’s why; an Artificial Neural Network (ANN) has been developed here for proper estimation considering only ∼1% and 1.5% errors with respect to the simulated and measured responses, respectively.

Comprehensive Evaluation of End-Point Free Energy Methods in DNA-Ligand Interaction Predictions.

Deoxyribonucleic acid (DNA) serves as a repository of genetic information in cells and is a critical molecular target for various antibiotics and anticancer drugs. A profound understanding of small molecule interaction with DNA is crucial for the rational design of DNA-targeted therapies. While the molecular mechanics/Poisson-Boltzmann surface area (MM/PBSA) and molecular mechanics/generalized Born surface area (MM/GBSA) approaches have been well established for predicting protein-ligand binding, their application to DNA-ligand interactions has been less explored. In this study, we systematically investigated the binding of 13 diverse small molecules to DNA, evaluating the accuracy of DNA-ligand interaction predictions across different solvation approaches, interior dielectric constants (εin), and molecular force fields. Our results demonstrate that MM/PBSA, using energy-minimized structures (the bsc1 force field and εin = 20), provides the best correlation (Rp = -0.742) with experimental binding affinities, surpassing the performance of rDock scoring functions (best Rp = -0.481). Notably, the interior dielectric constant was found to significantly impact DNA-ligand binding free energy predictions, especially for MM/PBSA. Moreover, both MM/PBSA and MM/GBSA predictions (εin = 16 or 20) exhibited superior performance in distinguishing native-like binding modes within the top-10 poses from decoys, compared to the molecular docking tools used in this study. However, the popular docking software PLANTS demonstrates notable efficacy in predicting the top-1 binding pose. Given the considerably higher computational cost of MM/PBSA, MM/GBSA rescoring with higher εin = 16 or 20 is more efficient for recognizing the native-like binding poses for DNA-ligand systems. This study presents the first detailed exploration of end-point free energy calculations in the context of DNA-ligand interactions and offers valuable insights for the application of the MM/PB(GB)SA methods in this domain.

Characteristics and mechanism of MBT anomaly of Karakum desert related with the Hindu Kush earthquake

AbstarctThe Hindu Kush is seismically active zone locates to the southwest of Pamir Plateau. Earthquakes are frequent here, but very a few relevant studies on earthquake anomalies was found. We investigated the abnormal change of satellite microwave brightness temperature (MBT) related with the recent Mw 6.4 earthquake occurred on January 11, 2024 near the Karakum Desert, Hindu Kush. We found a significant positive MBT anomaly appeared in the eastern part of Karakum Desert, on the immediate west of the epicenter, from three days before and two days after the earthquake. The temporal characteristics of the positive MBT anomaly can be described in sequence as follows: pre-earthquake (pre-EQ) rising, near-earthquake (near-EQ) enhancing, co-earthquake (co-EQ) peaking, after-earthquake (after-EQ) persisting and dissipating eventually. Validating with multi-source auxiliary data such as surface temperature (ST), microwave polarization difference index (MPDI), soil moisture (SM), rainfall and snowfall, we confirmed the positive MBT anomaly appeared in the Karakum Desert from January 10 to January 13 was attributed to the seismic activity but not meteorological factors. The upward transfer of P-hole particles, activated in the deep hypocenter area by accumulated crustal stress during the pre-, co- and after-EQ period, to the Quaternary surface along the stress gradient, was believed to have reduced the local ground surface dielectric constant and amplified the microwave radiation, which leading subsequently to the positive MBT anomalies. In addition, we found there was also abnormal locally high CH4 concentration occurred near the epicenter one day before the earthquake, which was probably related to the fault relaxing and CH4 releasing before the impending earthquake. This study has reference significance for identifying potential MBT anomalies during the seismogenic period and for the earthquake early warning in Hindu Kush region.

Overcoming Energy Storage-Loss Trade-Offs in Polymer Dielectrics Through the Synergistic Tuning of Electronic Effects in π-Conjugated Polystyrenes.

Achieving high-performance dielectric materials remains a significant challenge due to the inherent trade-offs between high energy storage density and low energy loss. A central difficulty lies in identifying a suitable dipolar unit that can enhance the polarity and dielectric constant of the material while effectively suppressing the high energy losses associated with polarization relaxation, charge injection, and conduction. To address this, a novel strategy is proposed that introduces electron-donating and electron-withdrawing substituents on the benzene ring of polystyrene-based polymers, creating bulky dipole groups that are resistant to reorientation under an electric field. This approach mitigates relaxation losses associated with dipole reorientation and manipulates the band structure via substituent modification to suppress conduction losses. Additionally, the deformation of the π-electron cloud under an electric field enhances the dielectric constant and energy storage density. Ultimately, the optimized chlorostyrene-methyl methacrylate (MMA) copolymer exhibits an 85% discharge efficiency and an energy storage density of 18.3 J cm- 3, nearly three times that of styrene-based copolymers under the same conditions. This study introduces a new approach for designing high-energy density, low-loss polymer dielectric materials by precisely controlling electron-donating and electron-withdrawing effects to modulate the distribution of π-conjugated electron clouds.