Browse
Submit Data
Databases
API
Help

Dataset Information

10 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Synthesis of Superheat-Resistant Polyimides with Enhanced Dielectric Constant by Introduction of Cu(??)-Coordination.

ABSTRACT: To achieve polyimide-metal complexes with enhanced properties, 5-amine-2-(5-aminopyridin-2-yl)-1-methyl-benzimidazole (PyMePABZ) that contains stiff 2-(2'-pyridyl)benzimidazole (PyBI) was synthesized and exploited to construct the Cu(??)-crosslinked polyimides (Cu-PIs). These Cu-PIs exhibited higher dielectric, thermal, and mechanical properties with an increase in Cu2+ content. Among them, their dielectric constants (?rS) were up to 43% superior to that of the neat PI, glass transition temperatures (Tgs) were all over 400 °C, and 5% weight loss temperature (T5%) maintained beyond 500 °C. These data indicate that the metal coordination crosslinking provided a useful guide to develop high performance PIs which possess potential application as useful high temperature capacitors.

SUBMITTER: Qian G

PROVIDER: S-EPMC7077670 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Synthesis of Superheat-Resistant Polyimides with Enhanced Dielectric Constant by Introduction of Cu(ΙΙ)-Coordination.

Qian Guangtao G Hu Mengjie M Zhang Shangying S Wang Mengxia M Chen Chunhai C Yao Jianan J

Polymers 20200213 2

To achieve polyimide-metal complexes with enhanced properties, 5-amine-2-(5-aminopyridin-2-yl)-1-methyl-benzimidazole (PyMePABZ) that contains stiff 2-(2'-pyridyl)benzimidazole (PyBI) was synthesized and exploited to construct the Cu(ΙΙ)-crosslinked polyimides (Cu-PIs). These Cu-PIs exhibited higher dielectric, thermal, and mechanical properties with an increase in Cu2+ content. Among them, their dielectric constants (εrS) were up to 43% superior to that of the neat PI, gla ...[more]

PMID: 32069842

Similar Datasets

Temperature-Resistant Intrinsic High Dielectric Constant Polyimides: More Flexibility of the Dipoles, Larger Permittivity of the Materials.

Project description:High dielectric constant polymers have been widely studied and concerned in modern industry, and the induction of polar groups has been confirmed to be effective for high permittivity. However, the way of connection of polar groups with the polymer backbone and the mechanism of their effect on the dielectric properties are unclear and rarely reported. In this study, three polyimides (C0-SPI, C1-SPI, and C2-SPI) with the same rigid backbone and different linking groups to the dipoles were designed and synthesized. With their rigid structure, all of the polyimides show excellent thermal stability. With the increase in the flexibility of linking groups, the dielectric constant of C0-SPI, C1-SPI, and C2-SPI enhanced in turn, showing values of 5.6, 6.0, and 6.5 at 100 Hz, respectively. Further studies have shown that the flexibility of polar groups affected the dipole polarization, which was positively related to the dielectric constant. Based on their high permittivity and high temperature resistance, the polyimides exhibited outstanding energy storage capacity even at 200 °C. This discovery reveals the behavior of the dipoles in polymers, providing an effective strategy for the design of high dielectric constant materials.

| S-EPMC9571362 | biostudies-literature

Studies on Magnetic and Dielectric Properties of Antiferromagnetically Coupled Dinuclear Cu(II) in a One-Dimensional Cu(II) Coordination Polymer.

Project description:A one-dimensional Cu(II) coordination polymer with encapsulated antiferromagnetically coupled binuclear Cu(II) has been synthesized by using 5-nitroisophthalic acid (5-N-IPA) and 4-aminopyridine (4-APY) [Cu2(5-N-IPA)2(4-APY)4] n (1). Electrical properties are examined by complex impedance (Z*), dielectric permittivity (?*), and ac conductivity studies at different frequencies (10 kHz-5 MHz) and temperatures (253-333 K). The contribution of grain and grain boundary has been explained by a different theoretical model. The variable temperature magnetic susceptibility data for compound 1 were recorded between 300 and 2 K. The shape of the curve (?M T vs T) indicates dominant antiferromagnetic coupling, which results from the interaction between the copper(II) atoms.

| S-EPMC6964276 | biostudies-literature

Enhanced Sinterability, Thermal Conductivity and Dielectric Constant of Glass-Ceramics with PVA and BN Additions.

Project description:With the rapid development of the microelectronics industry, many efforts have been made to improve glass-ceramics' sinterability, thermal conductivity, and dielectric properties, which are essential components of electronic materials. In this study, low-alkali borosilicate glass-ceramics with PVA addition and glass-BN composites were prepared and successfully sintered at 770 °C. The phase composition, density, microstructure, thermal conductivity, and dielectric constant were investigated. It was shown that PVA addition contributes to the densification process of glass-ceramics (~88% relative density, with closed/open pores in the microstructure) and improves the thermal conductivity of glass material from 1.489 to 2.453 W/K.m. On the other hand, increasing BN addition improves microstructures by decreasing porosities and thus increasing relative densities. A glass-12 wt. % BN composite sample exhibited almost full densification after sintering and presented apparent and open pores of 2.6 and 0.08%, respectively. A high thermal conductivity value of 3.955 W/K.m and a low dielectric constant of 3.00 (at 5 MHz) were observed in this material. Overall, the resulting glass-ceramic samples showed dielectric constants in the range of 2.40-4.43, providing a potential candidate for various electronic applications.

| S-EPMC8910993 | biostudies-literature

Mechanochemically-Assisted Synthesis of Polyimides.

Project description:Polyimides were obtained in 99 % yield in under 1 h through the "beat and heat" approach, involving solvent-free vibrational ball milling and a thermal treatment step. The influence of a plethora of additives was explored, such as Lewis acids, Lewis bases, and dehydrating agents, and the mechanochemical reaction was identified to run via a polyamic acid intermediate. The protocol was adopted to a range of substrates inaccessible through solution-based processes, including perylene tetracarboxylic acid dianhydride and melamine. Furthermore, quantum chemical calculations were conducted to identify the water removal as the crucial step in the reaction mechanism. The presented method is substantially faster and more versatile than the solution-based process.

| S-EPMC9299604 | biostudies-literature

Negative dielectric constant of water confined in nanosheets.

Project description:Electric double-layer capacitors are efficient energy storage devices that have the potential to account for uneven power demand in sustainable energy systems. Earlier attempts to improve an unsatisfactory capacitance of electric double-layer capacitors have focused on meso- or nanostructuring to increase the accessible surface area and minimize the distance between the adsorbed ions and the electrode. However, the dielectric constant of the electrolyte solvent embedded between adsorbed ions and the electrode surface, which also governs the capacitance, has not been previously exploited to manipulate the capacitance. Here we show that the capacitance of electric double-layer capacitor electrodes can be enlarged when the water molecules are strongly confined into the two-dimensional slits of titanium carbide MXene nanosheets. Using electrochemical methods and theoretical modeling, we find that dipolar polarization of strongly confined water resonantly overscreens an external electric field and enhances capacitance with a characteristically negative dielectric constant of a water molecule.

| S-EPMC6382890 | biostudies-literature

Model-Based Dielectric Constant Estimation of Polymeric Nanocomposite.

Project description:The interphase region widely exists in polymer-based nanocomposites, which affects the dielectric properties of the nanocomposites. General models, such as the Knott model, are often used to predict the dielectric constant of nanocomposites, while the model does not take the existence of interphase into account, which leads to a large deviation between the predicted results and the experimental values. In this study, a developed Knott model is proposed by introducing the interphase region and appropriately assuming the properties of the interphase. The modeling results based on the developed model are in good agreement with the experimental data, which verifies the high accuracy of the development model. The influence of nanoparticle loading on the effective volume fraction is further studied. In addition, the effects of the polymer matrix, nanoparticles, interphase dielectric and thickness, nanoparticle size and volume fraction on the dielectric properties of the nanocomposites are also investigated. The results show that polymer matrix or nanoparticles with a high dielectric and thick interphase can effectively improve the dielectric properties of the materials. Small size nanoparticles with high concentrations are more conducive to improving the dielectric properties of the nanocomposites. This study demonstrates that the interphase properties have an important impact on the dielectric properties of nanocomposites, and the developed model is helpful to accurately predict the dielectric constant of polymer-based nanocomposites.

| S-EPMC8955738 | biostudies-literature

Frequency-Dependent Dielectric Permittivity and Water Permeability in Ordered Mesoporous Silica-Grafted Fluorinated Polyimides

Project description: Not available

| S-EPMC11207492 | biostudies-literature

Can the Dielectric Constant of Fullerene Derivatives Be Enhanced by Side-Chain Manipulation? A Predictive First-Principles Computational Study.

Project description:The low efficiency of organic photovoltaic (OPV) devices has often been attributed to the strong Coulombic interactions between the electron and hole, impeding the charge separation process. Recently, it has been argued that by increasing the dielectric constant of materials used in OPVs, this strong interaction could be screened. In this work, we report the application of periodic density functional theory together with the coupled perturbed Kohn-Sham method to calculate the electronic contribution to the dielectric constant for fullerene C60 derivatives, a ubiquitous class of molecules in the field of OPVs. The results show good agreement with experimental data when available and also reveal an important undesirable outcome when manipulating the side chain to maximize the static dielectric constant: in all cases, the electronic contribution to the dielectric constant decreases as the side chain increases in size. This information should encourage both theoreticians and experimentalists to further investigate the relevance of contributions to the dielectric constant from slower processes like vibrations and dipolar reorientations for facilitating the charge separation, because electronically, enlarging the side chain of conventional fullerene derivatives only lowers the dielectric constant, and consequently, their electronic dielectric constant is upper bound by the one of C60.

| S-EPMC5911807 | biostudies-literature

Synthesis of BaTiO3 nanoparticles as shape modified filler for high dielectric constant ceramic-polymer composite.

Project description:Coral-like structured barium titanate (BaTiO3) nanoparticles were synthesized as filler for a high dielectric elastomer. The nanoparticle size, and shape, and the reactivity of the synthesis were modified according to temperature, time, pH, and precursor materials. Dielectric properties of poly(dimethylsiloxane) (PDMS) composites were estimated by volume fractions of BaTiO3 of 5, 10, and 15 vol% for both sphere and coral-like shapes. As a result, coral-like BaTiO3-PDMS composites had the highest dielectric constant of 10.97, which was 64% higher than the spherical BaTiO3-PDMS composites for the 15 vol% fraction. Furthermore, the phase transition process and surface modification were applied to increase the dielectric properties through calcination and improved particle dispersion in the elastomer using polyvinylpyrrolidone (PVP). The dispersion of the PVP coated BaTiO3-PDMS composite was improved compared to pristine BaTiO3 as shown by SEM imaging. The coral-like BaTiO3 embedded composite could be used for electronic devices such as piezoelectric devices or electro-adhesive grippers, which require flexible and high dielectric materials.

| S-EPMC9055919 | biostudies-literature

Approaching subthreshold-swing limit for thin-film transistors by using a giant-dielectric-constant gate dielectric.

Project description:Low-temperature giant-dielectric-constant thin films (In0.0025Nb0.0025Ti0.995O2) fabricated with simple radio frequency (RF) sputtering on glass substrates are employed as the gate dielectrics for thin-film transistors (TFTs) for the first time. The 380 nm-thick In0.0025Nb0.0025Ti0.995O2 film exhibited a quasi-static capacitance of as high as 36 156 nF cm-2 with a quasi-static permittivity of 15 525 (and 7607 nF cm-2 at 1 kHz). Indium zinc oxide (IZO) TFTs with In0.0025Nb0.0025Ti0.995O2 gate dielectrics exhibited high output current at low operation voltage and little hysteresis in the transfer curves between forward and reverse sweeps. The subthreshold swing (SS) of the IZO TFTs is 0.068 V dec-1, very close to the lowest limit of the SS of the field-effect transistors (0.06 V dec-1). The results also proves that the lowest limit of the SS (0.06 V dec-1) cannot be broken no matter how high the gate dielectric capacitance is (except for negative capacitors). The TFTs demonstrate the potential for the applications in low-power circuits or flat-panel displays.

| S-EPMC9070635 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data