With the rapid development of 5G information technology,thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent.In this work,“high-temperature...With the rapid development of 5G information technology,thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent.In this work,“high-temperature solid-phase&diazonium salt decomposition”method is carried out to prepare benzidine-functionalized boron nitride(m-BN).Subsequently,m-BN/poly(pphenylene benzobisoxazole)nanofiber(PNF)nanocomposite paper with nacremimetic layered structures is prepared via sol–gel film transformation approach.The obtained m-BN/PNF nanocomposite paper with 50 wt%m-BN presents excellent thermal conductivity,incredible electrical insulation,outstanding mechanical properties and thermal stability,due to the construction of extensive hydrogen bonds andπ–πinteractions between m-BN and PNF,and stable nacre-mimetic layered structures.Itsλ∥andλ_(⊥)are 9.68 and 0.84 W m^(-1)K^(-1),and the volume resistivity and breakdown strength are as high as 2.3×10^(15)Ωcm and 324.2 kV mm^(-1),respectively.Besides,it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640°C,showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment.展开更多
The preparation of PPy/PPTA conductive composite films by electrochemical method is presented.The first step is to cast a thin layer of poly (p-phenylene-terephthalamide) (PPTA) on a slice of Pt working electrode. The...The preparation of PPy/PPTA conductive composite films by electrochemical method is presented.The first step is to cast a thin layer of poly (p-phenylene-terephthalamide) (PPTA) on a slice of Pt working electrode. The second step is to electrochemically polymerize pyrrole on the PPTA/Pt working electrode. Both of the electrical conductivity and the mechanical properties of the PPy/PPTA composite film are better than those of the pure PPy film, and the film has excellent flexibility at low temperature, even in liquid nitrogen.The SEM picture of the cross-section of PPy,/PPTA composite film showed that the two components were well mixed.Cyclic voltammograms of PPy,/PPTA film in aqueous solution showed that the conductive films could be reduced and reoxidized.展开更多
The poly(epoxy-N-methylaniline)conductive organic carrier was used as the bonding phase of the low-temperature conductive silver paste.Then,this was mixed with different proportions of silver powder to prepare the low...The poly(epoxy-N-methylaniline)conductive organic carrier was used as the bonding phase of the low-temperature conductive silver paste.Then,this was mixed with different proportions of silver powder to prepare the low-temperature conductive silver paste.Afterwards,the effect of the conductive organic carrier on the properties of the low-temperature conductive silver paste was determined by IR,DMA and SEM.The results revealed that the prepared conductive paste has good conductivity,film-forming performance,printing performance,low-temperature curing performance,and anti-aging performance.When the mass percentage of the bonding phase/conductive phase was 40/60,the lowest volume resistivity of the conductive silver paste was 4.9×10^(−6)Ω⋅cm,and the conductivity was the best.展开更多
In order to explore the thermal conductivity of the natural poly-mineral rock,numerical tests of rock models with randomly-distributed components were conducted and compared with each other.Elaborately designed Monte ...In order to explore the thermal conductivity of the natural poly-mineral rock,numerical tests of rock models with randomly-distributed components were conducted and compared with each other.Elaborately designed Monte Carlo method was adopted to ingratiate the requirement of the random characteristics of grain size and the grains'spatial distribution.This requirement was fulfilled by clustering the randomly generated unstructured tetrahedral elements in full three dimensions.Natural rocks are consisted of randomly distributed crystal particles or intergranular minerals.Our primary results verify that the thermal conductivity of the rock is strongly sensitive to the ingredients' volume fraction and their spatial distribution.Furthermore,we proved that,in order to reduce the measurement error to a reasonable range,the numerical specimen must be large enough or include sufficient number of mineral particles.Our numerical test results are in accordance with a variety of empirical formulas which are currently employed in petrology.展开更多
Network polymer electrolytes with free oligo(oxyethylene) chains as internal plasticizers were prepared by cross-linking poly(ethylene glycol) acrylates. The effects of salt concentration and properties of internal pl...Network polymer electrolytes with free oligo(oxyethylene) chains as internal plasticizers were prepared by cross-linking poly(ethylene glycol) acrylates. The effects of salt concentration and properties of internal plasticizers on ionic conductivity were studied.展开更多
The polyaniline (PAn)/poly(vinyl alcohol) (PVA) conductive composite film is synthesized with perchloric acid (HClO 4) as the dopant and oxidant in reaction system by electrochemical polymerization. The result shows t...The polyaniline (PAn)/poly(vinyl alcohol) (PVA) conductive composite film is synthesized with perchloric acid (HClO 4) as the dopant and oxidant in reaction system by electrochemical polymerization. The result shows that this composite film has very high conductive properties, the maximum value of conductivity reaches 0.173 S/cm at the concentration 0.75 mol. The influences of HClO 4 on the conductivity of the composite film are investigated.In addition,the electrode reaction progress is discussed with the result that obtained from SEM and FTIR analyzing.展开更多
The ionic conductive elastomers show great promise in multifunctional wearable electronics,but they currently suffer from liquid leakage/evaporation or mechanical compliance.Developing ionic conductive elastomers inte...The ionic conductive elastomers show great promise in multifunctional wearable electronics,but they currently suffer from liquid leakage/evaporation or mechanical compliance.Developing ionic conductive elastomers integrating non-volatility,mechanical robustness,superior ionic conductivity,and ultra-stretchability remains urgent and challenging.Here,we developed a healable,robust,and conductive elastomer via impregnating free ionic liquids(ILs)into the ILs-multigrafted poly(urethane-urea)(PUU)elastomer networks.A crucial strategy in the molecular design is that imidazolium cations are largely introduced by double-modification of PUU and centipede-like structures are obtained,which can lock the impregnated ILs through strong ionic interactions.In this system,the PUU matrix contributes outstanding mechanical properties,while the hydrogen bonds and ionic interactions endow the elastomer with self-healing ability,conductivity,as well as non-volatility and transparency.The fabricated ionic conductive elastomers show good conductivity(3.8×10^(-6) S·cm^(-1)),high mechanical properties,including tensile stress(4.64 MPa),elongation(1470%),and excellent healing ability(repairing efficiency of 90%after healing at room temperature for 12 h).Significantly,the conductive elastomers have excellent antifatigue properties,and demonstrate a highly reproducible response after 1000 uninterrupted extension-release cycles.This work provides a promising strategy to prepare ionic conductive elastomers with excellent mechanical properties and stable sensing capacity,and further promote the development of mechanically adaptable intelligent sensors.展开更多
A polymer electrolyte based on poly(vinylidene) fluoride-hexafluoropropylene was prepared by evaporating the solvent of dimethyl formamide, and non-woven fabric was used to reinforce the mechanical strength of polymer...A polymer electrolyte based on poly(vinylidene) fluoride-hexafluoropropylene was prepared by evaporating the solvent of dimethyl formamide, and non-woven fabric was used to reinforce the mechanical strength of polymer electrolyte and maintain a good interfacial property between the polymer electrolyte and electrodes. Polymer lithium batteries were assembled by using LiCoO2 as cathode material and lithium foil as anode material. Scanning electron microscopy, alternating current impedance, linear sweep voltammetry and charge-discharge tests were used to study the properties of polymer membrane and polymer Li-ion batteries. The results show that the technics of preparing polymer electrolyte by directly evaporating solvent is simple. The polymer membrane has rich micro-porous structure on both sides and exhibits 280% uptake of electrolyte solution. The electrochemical stability window of this polymer electrolyte is about 5.5 V, and its ionic conductivity at room temperature reaches 0.151 S/m. The polymer lithium battery displays an initial discharge capacity of 138 mA·h/g and discharge plateau of about 3.9 V at 0.2 current rate. After 30 cycles, its loss of discharge capacity is only 2%. When the battery discharges at 0.5 current rate, the voltage plateau is still 3.7 V. The discharge capacities of 0.5 and 1.0 current rates are 96% and 93% of that of 0.1 current rate, respectively.展开更多
Polyethylene oxide(PEO)-based electrolytes have obvious merits such as strong ability to dissolve salts(e.g.,LiTFSI)and high flexibility,but their applications in solid-state batteries is hindered by the low ion condu...Polyethylene oxide(PEO)-based electrolytes have obvious merits such as strong ability to dissolve salts(e.g.,LiTFSI)and high flexibility,but their applications in solid-state batteries is hindered by the low ion conductance and poor mechanical and thermal properties.Herein,poly(m-phenylene isophthalamide)(PMIA)is employed as a multifunctional additive to improve the overall properties of the PEO-based electrolytes.The hydrogen-bond interactions between PMIA and PEO/TFSI-can effectively prevent the PEO crystallization and meanwhile facilitate the LiTFSI dissociation,and thus greatly improve the ionic conductivity(two times that of the pristine electrolyte at room temperature).With the incorporation of the high-strength PMIA with tough amide-benzene backbones,the PMIA/PEO-LiTFSI composite polymer electrolyte(CPE)membranes also show much higher mechanical strength(2.96 MPa),thermostability(4190℃)and interfacial stability against Li dendrites(468 h at 0.10 mA cm-2)than the pristine electrolyte(0.32 MPa,364℃and short circuit after 246 h).Furthermore,the CPE-based LiFePO4/Li cells exhibit superior cycling stability(137 mAh g^-1 with 93%retention after 100 cycles at 0.5 C)and rate performance(123 mAh g^-1 at 1.0 C).This work provides a novel and effective CPE structure design strategy to achieve comprehensively-upgraded electrolytes for promising solid-state battery applications.展开更多
Microporous poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)membranes following supercritical CO_2 induced phase separation process were prepared using four solvents.The solid electrolytes of PVDF-HFP were f...Microporous poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)membranes following supercritical CO_2 induced phase separation process were prepared using four solvents.The solid electrolytes of PVDF-HFP were formed by microporous PVDF-HFP membranes filled and swollen by a liquid electrolyte.The effect of the solvents on the morphology and structure,electrolyte absorptions and lithium ionic conductivity of the activated membranes were investigated.It was approved that all the membrane had the similar...展开更多
Crosslinked poly(vinyl alcohol)(PVA)based composite films were prepared as polyelectrolyte membranes for low temperature direct ethanol fuel cells(DEFC).The membranes were functionalised by means of the addition of gr...Crosslinked poly(vinyl alcohol)(PVA)based composite films were prepared as polyelectrolyte membranes for low temperature direct ethanol fuel cells(DEFC).The membranes were functionalised by means of the addition of graphene oxide(GO)and sulfonated graphene oxide(SGO)and crosslinked with sulfosuccinic acid(SSA).The chemical structure was corroborated and suitable thermal properties were found.Although the addition of GO and SGO slightly decreased the proton conductivity of the membranes,a significant reduction of the ethanol solution swelling and crossover was encountered,more relevant for those functionalised with SGO.In general,the composite membranes were stable under simulated service conditions.The addition of GO and SGO particles permitted to buffer the loss and almost retain similar proton conductivity than prior to immersion.These membranes are alternative polyelectrolytes,which overcome current concerns of actual commercial membranes such as the high cost or the crossover phenomenon.展开更多
Ionic, electronic and mixed (ionic-electronic) conductivities of blends of poly(2-vinyl pyridine) (P2VP) and poly(ethylene oxide) (PEO) with high molecular weight after doped with LiClO4, TCNQ or LiClO4 and TCNQ were ...Ionic, electronic and mixed (ionic-electronic) conductivities of blends of poly(2-vinyl pyridine) (P2VP) and poly(ethylene oxide) (PEO) with high molecular weight after doped with LiClO4, TCNQ or LiClO4 and TCNQ were investigated. Effects of LiClO4 and TCNQ concentrations on the conductivity of PEO/P2VP/LiClO4 or TCNQ blend were studied. The ionic conductivity of PEO/P2VP/LiClO4 blend increases with increasing PEO content. At a Li/ethylene bride molar ratio of 0.10 and a TCNQ/2-vinyl pyridine molar ratio of 0.5, the mixed conductivity of PEO/P2VP/LiClO4/TCNQ is higher than the total of ionic conductivity of PEO/P2VP/LiClO4 and electronic conductivity of PEO/P2VP/TCNQ when the weight ratio of PEO and P2VP is 6/4 or 5/5. Scanning electron microscopy (SEM) on the broken cross-section of the PEO/P2VP/LiClO4 blend and differential scanning calorimetry (DSC) results show that LiClO4 could act as a compatibilizer in the blend.展开更多
High quality poly(5-cyanoindole) (P5CI) films were electrosynthesized by direct anodic oxidation of 5-cyanoindole on stainless steel sheet in the mixed electrolytes of boron trifluoride diethyl etherate (BFEE) a...High quality poly(5-cyanoindole) (P5CI) films were electrosynthesized by direct anodic oxidation of 5-cyanoindole on stainless steel sheet in the mixed electrolytes of boron trifluoride diethyl etherate (BFEE) and diethyl ether (EE) (by volume 1:1) + 0,05 mol L^-1 Bu4NBF4. The film formed can be peeled off the electrode into freestanding films, The addition of EE into BFEE can improve the solubility of monomer. P5CI films obtained from this medium showed excellent electrochemical behavior with conductivity of 10^-2 S cm^-1, Structural studies showed that the polymerization of 5-cyanoindole occurred at the 2,3 position. As-formed P5CI films were thoroughly soluble in strong polar organic solvent dimethyl sulfoxide (DMSO) while partly soluble in tetrahydrofuran (THF) or acetone. Fluorescence spectral studies indicated that P5CI was a good blue-ight emitter.展开更多
Polymer electrolytes based on poly (methylsiloxane-g-ethylene oxide) and LiClO_4 have been prepared. The network films crosslinked by a crosslinking agent are found to exhibit a considerably high ionic conductivity of...Polymer electrolytes based on poly (methylsiloxane-g-ethylene oxide) and LiClO_4 have been prepared. The network films crosslinked by a crosslinking agent are found to exhibit a considerably high ionic conductivity of about 10^(-4) Scm^(-1) at room temperature and have good flexibility.展开更多
A kind of small band-gap conjugated polymers-poly (pyrrolyl methines) and their precursors-(poly pyrrolyl methanes) have been synthesized by a simple method and characterized by (HNMR)-H-1, FT-IR, TGA and UV-Vis. Thes...A kind of small band-gap conjugated polymers-poly (pyrrolyl methines) and their precursors-(poly pyrrolyl methanes) have been synthesized by a simple method and characterized by (HNMR)-H-1, FT-IR, TGA and UV-Vis. These polymers can be dissolved in high polar solvents such as DMSO, DMF or NMP. The results reveals that the band-gap of the synthesized conjugated polymers are in the range of 0.96similar to1.14 eV and they all belong to the small band-gap polymers. The conductivity of doped products with iodine is in the range of semiconductor.展开更多
[Objective] This paper was to introduce the chemical oxidative synthesis process, properties and test methods of 3,4-ethylenedioxythiophene(EDOT). [Method] The poor water solubility of EDOT was solved by using polyeth...[Objective] This paper was to introduce the chemical oxidative synthesis process, properties and test methods of 3,4-ethylenedioxythiophene(EDOT). [Method] The poor water solubility of EDOT was solved by using polyethylene glycol 20000(PEG) as the surfactant. The monomer was polymerized by chemical oxidative synthesis. The product was analyzed and verified by infrared spectrum, X-ray diffraction, ultraviolet-visible absorption spectra.[Result] The conductivity of the product was the best when the mass ratio of PEG and EDOT was 1∶1. The effects of oxidant dose and reaction time on the conductivity and yield of the product showed certain regularity. [Conclusion] EDOT could be polymerized by PEG and FeCl3, and the polymerization product was PEDOT.展开更多
A ternary hybrid membrane architecture consisting of sulfonated fluorinated multi-block copolymer (SFMC), sulfonated (poly ether ether ketone) (SPEEK) and I or 5 wt% graphene oxide (GO) was fabricated through ...A ternary hybrid membrane architecture consisting of sulfonated fluorinated multi-block copolymer (SFMC), sulfonated (poly ether ether ketone) (SPEEK) and I or 5 wt% graphene oxide (GO) was fabricated through a facile solution casting approach. The simple, but effective monomer sulfonation was performed for SFMC to create compact and rigid hydrophobic backbone structures, while conventional random sulfonation was carried-out for SPEEK. Hydrophilic-hydrophobic-hydrophilic structure of SFMC enhances the compatibility with SPEEK and GO and allows for an unprecedented approach to alter me- chanical strength and proton conductivity of ternary hybrid membrane, as verified from universal test machine (UTM) curves and alternating current (AC) impedance plots. The impact of GO integration on the morphology and roughness of hybrid membrane was scrutinized using field emission scanning electron microscope (FE-SEM) and atomic force microscope (AFM). Ternary hybrid showed uniform intercalation of GO nanosheets throughout the entire surface of membrane with an increased surface roughness of 8.91 nm. The constructed ternary hybrid membrane revealed excellent water absorption, ion exchange capacity and gas barrier properties, while retaining reasonable dimensional stability. The well-optimized ternary hybrid membrane containing 5 wt% GO revealed a maximum proton conductivity of 111.9 mS/cm, which is higher by a factor of two-fold with respect to that of bare SFMC membrane. The maximum PEMFC power density of 528.07mW/cm2 was yielded by ternary hybrid membrane at a load current density of 1321.1 mA/cm2 when operating the cell at 70 ℃ under 100% relative humidity (RH). In comparison, a maximum power density of only 182.06 mW/cm2 was exhibited by the bare SFMC membrane at a load current density of 455.56 mA/cm2 under same operating conditions.展开更多
The oxidative polycondensation reaction conditions of 4-[(4-hydroxybenzylidene) amino] phenol (4-HBAP) were studied with H2O2, air oxygen and NaOCl in an aqueous alkaline medium between 50 and 90℃. The structures...The oxidative polycondensation reaction conditions of 4-[(4-hydroxybenzylidene) amino] phenol (4-HBAP) were studied with H2O2, air oxygen and NaOCl in an aqueous alkaline medium between 50 and 90℃. The structures of the obtained monomer and polymer were confirmed by FT-IR, UV-Vis, 1H- and 13C-NMR and elemental analysis. The characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly[4-(4-hydroxybenzylidene amino) phenol] (P-4-HBAP) was found to be 48.3% (for H2O2 oxidant), 80.5% (for air O2 oxidant) and 86.4% (for NaOCl oxidant). According to the SEC analysis, the number-average molecular weight (Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) values of P-4-HBAP was found to be 8950, 10970 g tool^-1 and 1.225, respectively, using H202; and l l610, 15190 g tool^-1 and 1.308 respectively, using air 02 and 7900, 9610 g mol^-1 and 1.216, respectively, using NaOC1. According to TG-DTA analyses, P-4-HBAP was more stable than 4-HBAP against thermal decomposition. The weight loss of P-4-HBAP was found to be 49.27% at 1000℃. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) values calculated from electrochemical measurement. Electrochemical energy gaps (Eg') of 4-HBAP and P-4-HBAP were found to be -5.46, -5.28; -2.26, -2.67; 3.20 and 2.61 eV, respectively. According to UV-Vis measurements, optical band gap (Eg) of 4-HBAP and P-4-HBAP were found to be 3.34 and 3.01 eV, respectively. Also, antimicrobial activities of 4-HBAP and P-4-HBAP were examined against selected some bacteria. The electrical conductivity of the polymer was measured after doping with iodine.展开更多
Poly (β-carboxyethylmethylsiloxane)-LiClO_4 and poly (β-alkoxylethylmethylsiloxane)-LiClO_4 crosslinked fllms have been prepared. The ionic conductivity of the films depends on the polymer species, concentration of ...Poly (β-carboxyethylmethylsiloxane)-LiClO_4 and poly (β-alkoxylethylmethylsiloxane)-LiClO_4 crosslinked fllms have been prepared. The ionic conductivity of the films depends on the polymer species, concentration of lithium perchlorate, temperature and content of crosslinking agent. The effect of high polar organic solvent 1, 4-butyrolactone on the ionic conductivity and mechanical properties of poly (β-carhoxyethylmethylsiloxane )-LiClO_4 system was also investignied.展开更多
Poly(pyridinium ethyl methacrylate)was synthesized.The blends of polymeric solid anion conductor,P(PyEMAClO+4)/P(MEO_(16)—AM),were prepared. The temperature—dependence of both the conductivity and anionic mobility i...Poly(pyridinium ethyl methacrylate)was synthesized.The blends of polymeric solid anion conductor,P(PyEMAClO+4)/P(MEO_(16)—AM),were prepared. The temperature—dependence of both the conductivity and anionic mobility in the blends obey Arrhenius relationship,the transport of perchlorate anion being of thermal activation mechanism.Perchlorate anion is a free anion in the blends.展开更多
基金The authors are grateful for the support and funding from the Foundation of National Natural Science Foundation of China(52373089 and 51973173)Startup Foundation of Chongqing Normal University(23XLB011),Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202300561)Fundamental Research Funds for the Central Universities。
文摘With the rapid development of 5G information technology,thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent.In this work,“high-temperature solid-phase&diazonium salt decomposition”method is carried out to prepare benzidine-functionalized boron nitride(m-BN).Subsequently,m-BN/poly(pphenylene benzobisoxazole)nanofiber(PNF)nanocomposite paper with nacremimetic layered structures is prepared via sol–gel film transformation approach.The obtained m-BN/PNF nanocomposite paper with 50 wt%m-BN presents excellent thermal conductivity,incredible electrical insulation,outstanding mechanical properties and thermal stability,due to the construction of extensive hydrogen bonds andπ–πinteractions between m-BN and PNF,and stable nacre-mimetic layered structures.Itsλ∥andλ_(⊥)are 9.68 and 0.84 W m^(-1)K^(-1),and the volume resistivity and breakdown strength are as high as 2.3×10^(15)Ωcm and 324.2 kV mm^(-1),respectively.Besides,it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640°C,showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment.
文摘The preparation of PPy/PPTA conductive composite films by electrochemical method is presented.The first step is to cast a thin layer of poly (p-phenylene-terephthalamide) (PPTA) on a slice of Pt working electrode. The second step is to electrochemically polymerize pyrrole on the PPTA/Pt working electrode. Both of the electrical conductivity and the mechanical properties of the PPy/PPTA composite film are better than those of the pure PPy film, and the film has excellent flexibility at low temperature, even in liquid nitrogen.The SEM picture of the cross-section of PPy,/PPTA composite film showed that the two components were well mixed.Cyclic voltammograms of PPy,/PPTA film in aqueous solution showed that the conductive films could be reduced and reoxidized.
基金fund for this work was provided by the“Research on Key Technologies of Photosensitive Conductive Silver Paste Based on Domestic Circuit Protection Micro Chip Components”(Project No.BE2020008 and Supporting Author:Chen P).
文摘The poly(epoxy-N-methylaniline)conductive organic carrier was used as the bonding phase of the low-temperature conductive silver paste.Then,this was mixed with different proportions of silver powder to prepare the low-temperature conductive silver paste.Afterwards,the effect of the conductive organic carrier on the properties of the low-temperature conductive silver paste was determined by IR,DMA and SEM.The results revealed that the prepared conductive paste has good conductivity,film-forming performance,printing performance,low-temperature curing performance,and anti-aging performance.When the mass percentage of the bonding phase/conductive phase was 40/60,the lowest volume resistivity of the conductive silver paste was 4.9×10^(−6)Ω⋅cm,and the conductivity was the best.
基金supported by the National Science and Technology Project (No. Si-noProbe-07)National Basic Research Program of China (No. 2008cb425701)+1 种基金National Natural Science Foundation of China (No. 40774049)Institute of Earthquake Science,China Earthquake Administration,who provided us with the support from the collaborative project named as "Pre-study of several issues of testing ground for numerical forecast earthquakes in North China"
文摘In order to explore the thermal conductivity of the natural poly-mineral rock,numerical tests of rock models with randomly-distributed components were conducted and compared with each other.Elaborately designed Monte Carlo method was adopted to ingratiate the requirement of the random characteristics of grain size and the grains'spatial distribution.This requirement was fulfilled by clustering the randomly generated unstructured tetrahedral elements in full three dimensions.Natural rocks are consisted of randomly distributed crystal particles or intergranular minerals.Our primary results verify that the thermal conductivity of the rock is strongly sensitive to the ingredients' volume fraction and their spatial distribution.Furthermore,we proved that,in order to reduce the measurement error to a reasonable range,the numerical specimen must be large enough or include sufficient number of mineral particles.Our numerical test results are in accordance with a variety of empirical formulas which are currently employed in petrology.
文摘Network polymer electrolytes with free oligo(oxyethylene) chains as internal plasticizers were prepared by cross-linking poly(ethylene glycol) acrylates. The effects of salt concentration and properties of internal plasticizers on ionic conductivity were studied.
文摘The polyaniline (PAn)/poly(vinyl alcohol) (PVA) conductive composite film is synthesized with perchloric acid (HClO 4) as the dopant and oxidant in reaction system by electrochemical polymerization. The result shows that this composite film has very high conductive properties, the maximum value of conductivity reaches 0.173 S/cm at the concentration 0.75 mol. The influences of HClO 4 on the conductivity of the composite film are investigated.In addition,the electrode reaction progress is discussed with the result that obtained from SEM and FTIR analyzing.
基金supported by the National Natural Science Foundation of China(Nos.22275148,52203144,and 22375162)the Key R&D Project of Shaanxi Province(Nos.2023-YBGY-489 and 2023-YBGY-474)+3 种基金the Central Government Guides Local Science and Technology Development Fund Projects(No.2022ZY2-JCYJ-01-07)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2022-JQ136)the Fundamental Research Funds for the Central Universities(No.5000210717)the Foundation(No.2019KF04)of Guangxi Key Laboratory of Clean Pulp&Papermaking and Pollution Control,College of Light Industry and Food Engineering,Guangxi University for financial support.
文摘The ionic conductive elastomers show great promise in multifunctional wearable electronics,but they currently suffer from liquid leakage/evaporation or mechanical compliance.Developing ionic conductive elastomers integrating non-volatility,mechanical robustness,superior ionic conductivity,and ultra-stretchability remains urgent and challenging.Here,we developed a healable,robust,and conductive elastomer via impregnating free ionic liquids(ILs)into the ILs-multigrafted poly(urethane-urea)(PUU)elastomer networks.A crucial strategy in the molecular design is that imidazolium cations are largely introduced by double-modification of PUU and centipede-like structures are obtained,which can lock the impregnated ILs through strong ionic interactions.In this system,the PUU matrix contributes outstanding mechanical properties,while the hydrogen bonds and ionic interactions endow the elastomer with self-healing ability,conductivity,as well as non-volatility and transparency.The fabricated ionic conductive elastomers show good conductivity(3.8×10^(-6) S·cm^(-1)),high mechanical properties,including tensile stress(4.64 MPa),elongation(1470%),and excellent healing ability(repairing efficiency of 90%after healing at room temperature for 12 h).Significantly,the conductive elastomers have excellent antifatigue properties,and demonstrate a highly reproducible response after 1000 uninterrupted extension-release cycles.This work provides a promising strategy to prepare ionic conductive elastomers with excellent mechanical properties and stable sensing capacity,and further promote the development of mechanically adaptable intelligent sensors.
基金Project (2003AA32X010) supported by the National High Technology Research and Development Program of China
文摘A polymer electrolyte based on poly(vinylidene) fluoride-hexafluoropropylene was prepared by evaporating the solvent of dimethyl formamide, and non-woven fabric was used to reinforce the mechanical strength of polymer electrolyte and maintain a good interfacial property between the polymer electrolyte and electrodes. Polymer lithium batteries were assembled by using LiCoO2 as cathode material and lithium foil as anode material. Scanning electron microscopy, alternating current impedance, linear sweep voltammetry and charge-discharge tests were used to study the properties of polymer membrane and polymer Li-ion batteries. The results show that the technics of preparing polymer electrolyte by directly evaporating solvent is simple. The polymer membrane has rich micro-porous structure on both sides and exhibits 280% uptake of electrolyte solution. The electrochemical stability window of this polymer electrolyte is about 5.5 V, and its ionic conductivity at room temperature reaches 0.151 S/m. The polymer lithium battery displays an initial discharge capacity of 138 mA·h/g and discharge plateau of about 3.9 V at 0.2 current rate. After 30 cycles, its loss of discharge capacity is only 2%. When the battery discharges at 0.5 current rate, the voltage plateau is still 3.7 V. The discharge capacities of 0.5 and 1.0 current rates are 96% and 93% of that of 0.1 current rate, respectively.
基金supported partially by Natural Science Foundation of Beijing Municipality(L172036)Joint Funds of the Equipment Pre-Research and Ministry of Education(6141A020225)+3 种基金Par-Eu Scholars Program,Science and Technology Beijing 100 Leading Talent Training ProjectChina Postdoctoral Science Foundation(2018M631419)Fundamental Research Funds for Central Universities(2017ZZD02,2019QN001)NCEPU“Double First-Class”Graduate Talent Cultivation Program。
文摘Polyethylene oxide(PEO)-based electrolytes have obvious merits such as strong ability to dissolve salts(e.g.,LiTFSI)and high flexibility,but their applications in solid-state batteries is hindered by the low ion conductance and poor mechanical and thermal properties.Herein,poly(m-phenylene isophthalamide)(PMIA)is employed as a multifunctional additive to improve the overall properties of the PEO-based electrolytes.The hydrogen-bond interactions between PMIA and PEO/TFSI-can effectively prevent the PEO crystallization and meanwhile facilitate the LiTFSI dissociation,and thus greatly improve the ionic conductivity(two times that of the pristine electrolyte at room temperature).With the incorporation of the high-strength PMIA with tough amide-benzene backbones,the PMIA/PEO-LiTFSI composite polymer electrolyte(CPE)membranes also show much higher mechanical strength(2.96 MPa),thermostability(4190℃)and interfacial stability against Li dendrites(468 h at 0.10 mA cm-2)than the pristine electrolyte(0.32 MPa,364℃and short circuit after 246 h).Furthermore,the CPE-based LiFePO4/Li cells exhibit superior cycling stability(137 mAh g^-1 with 93%retention after 100 cycles at 0.5 C)and rate performance(123 mAh g^-1 at 1.0 C).This work provides a novel and effective CPE structure design strategy to achieve comprehensively-upgraded electrolytes for promising solid-state battery applications.
基金This work was financially supported by the China Postdoctoral Science Foundation(No.20060400436)the National Nature Foundation of China(No. 50433010)the National 973 Foundation of China(No.2003CB615705).
文摘Microporous poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)membranes following supercritical CO_2 induced phase separation process were prepared using four solvents.The solid electrolytes of PVDF-HFP were formed by microporous PVDF-HFP membranes filled and swollen by a liquid electrolyte.The effect of the solvents on the morphology and structure,electrolyte absorptions and lithium ionic conductivity of the activated membranes were investigated.It was approved that all the membrane had the similar...
基金the support of the European Union through the European Regional Development Funds(ERDF)The Spanish Ministry of Economy,Industry and Competitiveness,is thanked for the research project POLYDECARBOCELL(ENE2017-86711-C3-1-R)The Spanish Ministry of Education,Culture and Sports is thanked for the FPU grant for O.Gil-Castell(FPU13/01916)。
文摘Crosslinked poly(vinyl alcohol)(PVA)based composite films were prepared as polyelectrolyte membranes for low temperature direct ethanol fuel cells(DEFC).The membranes were functionalised by means of the addition of graphene oxide(GO)and sulfonated graphene oxide(SGO)and crosslinked with sulfosuccinic acid(SSA).The chemical structure was corroborated and suitable thermal properties were found.Although the addition of GO and SGO slightly decreased the proton conductivity of the membranes,a significant reduction of the ethanol solution swelling and crossover was encountered,more relevant for those functionalised with SGO.In general,the composite membranes were stable under simulated service conditions.The addition of GO and SGO particles permitted to buffer the loss and almost retain similar proton conductivity than prior to immersion.These membranes are alternative polyelectrolytes,which overcome current concerns of actual commercial membranes such as the high cost or the crossover phenomenon.
基金Project supported by the National Natural Science Foundation of China.
文摘Ionic, electronic and mixed (ionic-electronic) conductivities of blends of poly(2-vinyl pyridine) (P2VP) and poly(ethylene oxide) (PEO) with high molecular weight after doped with LiClO4, TCNQ or LiClO4 and TCNQ were investigated. Effects of LiClO4 and TCNQ concentrations on the conductivity of PEO/P2VP/LiClO4 or TCNQ blend were studied. The ionic conductivity of PEO/P2VP/LiClO4 blend increases with increasing PEO content. At a Li/ethylene bride molar ratio of 0.10 and a TCNQ/2-vinyl pyridine molar ratio of 0.5, the mixed conductivity of PEO/P2VP/LiClO4/TCNQ is higher than the total of ionic conductivity of PEO/P2VP/LiClO4 and electronic conductivity of PEO/P2VP/TCNQ when the weight ratio of PEO and P2VP is 6/4 or 5/5. Scanning electron microscopy (SEM) on the broken cross-section of the PEO/P2VP/LiClO4 blend and differential scanning calorimetry (DSC) results show that LiClO4 could act as a compatibilizer in the blend.
基金This work was supported by the Jiangxi Research Center for Material Science & Engineering(No.ZX200401008)the Jiangxi Science and Technology Normal University.
文摘High quality poly(5-cyanoindole) (P5CI) films were electrosynthesized by direct anodic oxidation of 5-cyanoindole on stainless steel sheet in the mixed electrolytes of boron trifluoride diethyl etherate (BFEE) and diethyl ether (EE) (by volume 1:1) + 0,05 mol L^-1 Bu4NBF4. The film formed can be peeled off the electrode into freestanding films, The addition of EE into BFEE can improve the solubility of monomer. P5CI films obtained from this medium showed excellent electrochemical behavior with conductivity of 10^-2 S cm^-1, Structural studies showed that the polymerization of 5-cyanoindole occurred at the 2,3 position. As-formed P5CI films were thoroughly soluble in strong polar organic solvent dimethyl sulfoxide (DMSO) while partly soluble in tetrahydrofuran (THF) or acetone. Fluorescence spectral studies indicated that P5CI was a good blue-ight emitter.
文摘Polymer electrolytes based on poly (methylsiloxane-g-ethylene oxide) and LiClO_4 have been prepared. The network films crosslinked by a crosslinking agent are found to exhibit a considerably high ionic conductivity of about 10^(-4) Scm^(-1) at room temperature and have good flexibility.
文摘A kind of small band-gap conjugated polymers-poly (pyrrolyl methines) and their precursors-(poly pyrrolyl methanes) have been synthesized by a simple method and characterized by (HNMR)-H-1, FT-IR, TGA and UV-Vis. These polymers can be dissolved in high polar solvents such as DMSO, DMF or NMP. The results reveals that the band-gap of the synthesized conjugated polymers are in the range of 0.96similar to1.14 eV and they all belong to the small band-gap polymers. The conductivity of doped products with iodine is in the range of semiconductor.
基金Natural Science Foundation of Guangxi Province(2017GXNSFAA198274)
文摘[Objective] This paper was to introduce the chemical oxidative synthesis process, properties and test methods of 3,4-ethylenedioxythiophene(EDOT). [Method] The poor water solubility of EDOT was solved by using polyethylene glycol 20000(PEG) as the surfactant. The monomer was polymerized by chemical oxidative synthesis. The product was analyzed and verified by infrared spectrum, X-ray diffraction, ultraviolet-visible absorption spectra.[Result] The conductivity of the product was the best when the mass ratio of PEG and EDOT was 1∶1. The effects of oxidant dose and reaction time on the conductivity and yield of the product showed certain regularity. [Conclusion] EDOT could be polymerized by PEG and FeCl3, and the polymerization product was PEDOT.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(No.20164030201070)supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT and future Planning(NRF-2017R1A2B4005230)
文摘A ternary hybrid membrane architecture consisting of sulfonated fluorinated multi-block copolymer (SFMC), sulfonated (poly ether ether ketone) (SPEEK) and I or 5 wt% graphene oxide (GO) was fabricated through a facile solution casting approach. The simple, but effective monomer sulfonation was performed for SFMC to create compact and rigid hydrophobic backbone structures, while conventional random sulfonation was carried-out for SPEEK. Hydrophilic-hydrophobic-hydrophilic structure of SFMC enhances the compatibility with SPEEK and GO and allows for an unprecedented approach to alter me- chanical strength and proton conductivity of ternary hybrid membrane, as verified from universal test machine (UTM) curves and alternating current (AC) impedance plots. The impact of GO integration on the morphology and roughness of hybrid membrane was scrutinized using field emission scanning electron microscope (FE-SEM) and atomic force microscope (AFM). Ternary hybrid showed uniform intercalation of GO nanosheets throughout the entire surface of membrane with an increased surface roughness of 8.91 nm. The constructed ternary hybrid membrane revealed excellent water absorption, ion exchange capacity and gas barrier properties, while retaining reasonable dimensional stability. The well-optimized ternary hybrid membrane containing 5 wt% GO revealed a maximum proton conductivity of 111.9 mS/cm, which is higher by a factor of two-fold with respect to that of bare SFMC membrane. The maximum PEMFC power density of 528.07mW/cm2 was yielded by ternary hybrid membrane at a load current density of 1321.1 mA/cm2 when operating the cell at 70 ℃ under 100% relative humidity (RH). In comparison, a maximum power density of only 182.06 mW/cm2 was exhibited by the bare SFMC membrane at a load current density of 455.56 mA/cm2 under same operating conditions.
基金This work was financially supported by the TUBITAK Grants Commission for a research grant(No.TBAG-2451(104T062)).
文摘The oxidative polycondensation reaction conditions of 4-[(4-hydroxybenzylidene) amino] phenol (4-HBAP) were studied with H2O2, air oxygen and NaOCl in an aqueous alkaline medium between 50 and 90℃. The structures of the obtained monomer and polymer were confirmed by FT-IR, UV-Vis, 1H- and 13C-NMR and elemental analysis. The characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly[4-(4-hydroxybenzylidene amino) phenol] (P-4-HBAP) was found to be 48.3% (for H2O2 oxidant), 80.5% (for air O2 oxidant) and 86.4% (for NaOCl oxidant). According to the SEC analysis, the number-average molecular weight (Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) values of P-4-HBAP was found to be 8950, 10970 g tool^-1 and 1.225, respectively, using H202; and l l610, 15190 g tool^-1 and 1.308 respectively, using air 02 and 7900, 9610 g mol^-1 and 1.216, respectively, using NaOC1. According to TG-DTA analyses, P-4-HBAP was more stable than 4-HBAP against thermal decomposition. The weight loss of P-4-HBAP was found to be 49.27% at 1000℃. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) values calculated from electrochemical measurement. Electrochemical energy gaps (Eg') of 4-HBAP and P-4-HBAP were found to be -5.46, -5.28; -2.26, -2.67; 3.20 and 2.61 eV, respectively. According to UV-Vis measurements, optical band gap (Eg) of 4-HBAP and P-4-HBAP were found to be 3.34 and 3.01 eV, respectively. Also, antimicrobial activities of 4-HBAP and P-4-HBAP were examined against selected some bacteria. The electrical conductivity of the polymer was measured after doping with iodine.
文摘Poly (β-carboxyethylmethylsiloxane)-LiClO_4 and poly (β-alkoxylethylmethylsiloxane)-LiClO_4 crosslinked fllms have been prepared. The ionic conductivity of the films depends on the polymer species, concentration of lithium perchlorate, temperature and content of crosslinking agent. The effect of high polar organic solvent 1, 4-butyrolactone on the ionic conductivity and mechanical properties of poly (β-carhoxyethylmethylsiloxane )-LiClO_4 system was also investignied.
文摘Poly(pyridinium ethyl methacrylate)was synthesized.The blends of polymeric solid anion conductor,P(PyEMAClO+4)/P(MEO_(16)—AM),were prepared. The temperature—dependence of both the conductivity and anionic mobility in the blends obey Arrhenius relationship,the transport of perchlorate anion being of thermal activation mechanism.Perchlorate anion is a free anion in the blends.