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Review of recent advances of polymer based dielectrics for high-energy storage in electronic power devices

Wenjie Sun, Jiale Mao, Shuang Wang, Lei Zhang, Yonghong Cheng

《化学科学与工程前沿(英文)》 2021年 第15卷 第1期   页码 18-34 doi: 10.1007/s11705-020-1939-4

摘要: Polymer-based dielectric capacitors are widely-used energy storage devices. However, although the functions of dielectrics in applications like high-voltage direct current transmission projects, distributed energy systems, high-power pulse systems and new energy electric vehicles are similar, their requirements can be quite different. Low electric loss is a critical prerequisite for capacitors for electric grids, while high-temperature stability is an essential pre-requirement for those in electric vehicles. This paper reviews recent advances in this area, and categorizes dielectrics in terms of their foremost properties related to their target applications. Requirements for polymer-based dielectrics in various power electronic equipment are emphasized, including high energy storage density, low dissipation, high working temperature and fast-response time. This paper considers innovations including chemical structure modification, composite fabrication and structure re-design, and the enhancements to material performances achieved. The advantages and limitations of these methods are also discussed.

关键词: dielectric capacitors     polymer-based dielectrics     energy density     dielectric loss     working temperature     frequency response    

Development of electrorheological chip and conducting polymer-based sensor

Xianzhou ZHANG, Weihua LI, Weijia WEN, Yanzhe WU, Gordon WALLACE,

《机械工程前沿(英文)》 2009年 第4卷 第4期   页码 393-396 doi: 10.1007/s11465-009-0043-8

摘要: This paper presents the development of an integrated sensor using two types of smart materials: electrorheological (ER) fluids and conducting polymers (CPs). The developed ER chip worked as an actuator, and it was driven by different voltages and control frequencies. When the four electrodes are controlled synchronously, the diaphragm acts as a vibrator whose frequency can be adjusted in accordance with the frequency of the electrical signals. The response signals of the CP sensor were recorded, and its properties were analyzed. Experimental results show that the amplitude decreases monotonically when the frequency increases, owing to the time delay in the pressure buildup in the ER chip. However, the displacement fluctuation of the diaphragm below 20Hz can be detected clearly even if the value is very low. When the vibration frequency is larger than 20Hz, the CP sensor can hardly detect the displacement fluctuation. Thus, the upper limit frequency that the CP sensor can detect is about 20Hz. The practical applications of this microdevice are also discussed.

关键词: electrorheological (ER) fluids     conducting polymer (CP)     polydimethylsioxane (PDMS)     driving frequency     amplitude     bubble counter    

Validation of polymer-based nano-iron oxide in further phosphorus removal from bioeffluent: laboratory

Ming HUA, Lili XIAO, Bingcai PAN, Quanxing ZHANG

《环境科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 435-441 doi: 10.1007/s11783-013-0508-1

摘要: The efficient removal of phosphorous from water is an important but challenging task. In this study, we validated the applicability of a new commercially available nanocomposite adsorbent, i.e., a polymer-based hydrated ferric oxide nanocomposite (HFO-201), for the further removal of phosphorous from the bioeffluent discharged from a municipal wastewater treatment plant, and the operating parameters such as the flow rate, temperature and composition of the regenerants were optimized. Laboratory-scale results indicate that phosphorous in real bioeffluent can be effectively removed from 0.92 mg·L to<0.5 mg·L (or even<0.1 mg·L as desired) by the new adsorbent at a flow rate of 50 bed volume (BV) per hour and treatable volume of 3500–4000 BV per run. Phosphorous removal is independent of the ambient temperature in the range of 15°C–40°C. Moreover, the exhausted HFO-201 can be regenerated by a 2% NaOH+ 5% NaCl binary solution for repeated use without significant capacity loss. A scaled-up study further indicated that even though the initial total phosphorus (TP) was as high as 2 mg·L , it could be reduced to<0.5 mg·L , with a working capacity of 4.4–4.8 g·L HFO-201. In general, HFO-201 adsorption is a choice method for the efficient removal of phosphate from biotreated waste effluent.

关键词: bioeffluent     phosphorus removal     nanocomposite adsorbent     hydrated ferric oxide    

Modeling and simulation of droplet translocation and fission by electrowetting-on-dielectrics (EWOD)

Nathan HOWELL, Weihua LI

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 376-388 doi: 10.1007/s11465-010-0104-z

摘要: This paper discusses methods of microfluidic droplet actuation by means of electrowetting-on-dielectrics (EWOD) and provides a technique for modeling and simulating a microfluidic device by using the computational fluid dynamics (CFD) program, Flow3D. Digital or droplet microfluidics implies the manipulation of droplets on a scale of nanoliters (10 L) to femtoliters (10 L), as opposed to continuous microfluidics that involve the control of continuous fluid within a channel. The two operations in focus here are droplet translocation (moving) and droplet fission (splitting), in which the pressures and velocities within the droplet are analyzed and compared to existing works, both theoretical and experimental. The variation in the pressure of the leading and trailing faces of a droplet indicates the variation in surface energy—an important parameter that explains how a droplet will move toward a region of higher electric potential. The higher voltage on one side of a droplet reduces surface energy, which leads to an induced pressure drop, thus resulting in fluid motion. Flow3D simulations are for both water and blood droplets at voltages between 50 V and 200 V, and the droplet size, surface properties (Teflon coated), and geometry of the system are kept constant for each operation. Some peculiarities of the simulation are brought to light, such as instabilities of the system to higher voltages and fluids with higher dielectric constants, as well as the creation of a tertiary droplet when the applied voltage causes a large enough force during fission. The force distribution across the droplet provides a general understanding of the electrowetting effect and more specifically allows for a comparison between the effects that different voltages have on the forces at the droplet surface. The droplet position and mean kinetic energy of the droplet are also investigated and compared to other works, proving the dynamics of a droplet motion found here.

关键词: electrowetting-on-dielectrics (EWOD)     electrowetting     microfluidics     droplet translocation     droplet fission     Flow3D     dielectric constant    

双氧原子掺杂的氮化硼材料用于吸附脱硫研究 Article

罗静, 魏延臣, 巢艳红, 王超, 李宏平, 熊君, 华明清, 李华明, 朱文帅

《工程(英文)》 2022年 第14卷 第7期   页码 86-93 doi: 10.1016/j.eng.2020.08.030

摘要:

氧原子普遍共存于六方氮化硼(h-BN)吸附剂中。如何利用h-BN中的氧原子以强化其与吸附质之间的相互作用,从而提高材料的吸附性能,是一个亟待解决课题。本文以聚合法构建氧原子晶格内部取代和边缘羟基化修饰的双氧原子位点改性BN(BN‒2O)材料。BN‒2O的边缘羟基氧原子能够增强二苯并噻吩(DBT)与其非均匀表面的π-π作用,从而促进多分子层型吸附过程。实验结果表明,相比边缘羟基取代BN(BN‒OH)材料,BN‒2O材料对燃油中DBT的吸附容量提升了12%。密度泛函理论计算还揭示了BN‒2O晶格内部的氧原子可以通过极化吸附质的方式增强其与BN‒2O之间的偶极作用,进一步提高BN‒2O从富含芳烃的燃油中选择性吸附DBT的能力,使得其在燃油吸附脱硫领域表现出更好的应用前景。吸附结果符合Freundlich模型和准二级动力学模型结果。因此,该聚合法同样可被应用于其他杂原子掺杂体系以提升吸附剂的吸附性能。

关键词: 聚合物基合成策略     内部取代BN     氧掺杂     吸附脱硫    

Assessing the effects of different dielectrics on environmentally conscious powder-mixed EDM of difficult-to-machine

Jagdeep SINGH,Rajiv Kumar SHARMA

《机械工程前沿(英文)》 2016年 第11卷 第4期   页码 374-387 doi: 10.1007/s11465-016-0388-8

摘要:

Electrical discharge machining (EDM) is a well-known nontraditional manufacturing process to machine the difficult-to-machine (DTM) materials which have unique hardness properties. Researchers have successfully performed hybridization to improve this process by incorporating powders into the EDM process known as powder-mixed EDM process. This process drastically improves process efficiency by increasing material removal rate, micro-hardness, as well as reducing the tool wear rate and surface roughness. EDM also has some input parameters, including pulse-on time, dielectric levels and its type, current setting, flushing pressure, and so on, which have a significant effect on EDM performance. However, despite their positive influence, investigating the effects of these parameters on environmental conditions is necessary. Most studies demonstrate the use of kerosene oil as dielectric fluid. Nevertheless, in this work, the authors highlight the findings with respect to three different dielectric fluids, including kerosene oil, EDM oil, and distilled water using one-variable-at-a-time approach for machining as well as environmental aspects. The hazard and operability analysis is employed to identify the inherent safety factors associated with powder-mixed EDM of WC-Co.

关键词: WC     hazard and operability analysis (HAZOP)     discharging     aerosol concentration     dielectrics     powders    

Development of an electrorheological chip and conducting polymer based sensor

Xianzhou ZHANG, Weihua LI, Weijia WEN, Yanzhe WU, Gordon WALLACE,

《机械工程前沿(英文)》 2009年 第4卷 第4期   页码 472-472 doi: 10.1007/s11465-009-0077-y

Numerical modeling of nonlinear deformation of polymer composites based on hyperelastic constitutive

Qingsheng YANG, Fang XU

《机械工程前沿(英文)》 2009年 第4卷 第3期   页码 284-288 doi: 10.1007/s11465-009-0067-0

摘要: Fiber reinforced polymer (FRP) composites exhibit nonlinear and hyperelastic characteristics under finite deformation. This paper investigates the macroscopic hyperelastic behavior of fiber reinforced polymer composites using a micromechanical model and finite deformation theory based on the hyperelastic constitutive law. The local stress and deformation of a representative volume element are calculated by the nonlinear finite element method. Then, an averaging procedure is used to find the homogenized stress and strain, and the macroscopic stress-strain curves are obtained. Numerical examples are given to demonstrate hyperelastic behavior and deformation of the composites, and the effects of the distribution pattern of fibers are also investigated to model the mechanical behavior of FRP composites.

关键词: composites     hyperelastic     finite deformation     homogenization     micromechanics    

Lignin-based polymer with high phenolic hydroxyl group content prepared by the alkyl chain bridging method

《化学科学与工程前沿(英文)》 2023年 第17卷 第8期   页码 1075-1084 doi: 10.1007/s11705-022-2272-x

摘要: Inspired by the importance of the phenolic group to the electron transporting property of hole transport materials, phenolic hydroxyl groups were introduced in lignosulfonate (LS) via the alkyl chain bridging method to prepare phenolated-lignosulfonate (PLS). The results showed that the phenolic group was boosted from 0.81 mmol∙g–1 of LS to 1.19 mmol∙g–1 of PLS. The electrochemical property results showed two oxidation peaks in the cyclic voltammogram (CV) curve of PLS, and the oxidation potential of the PLS-modified electrode decreased by 0.5 eV compared with that of LS. This result indicates that PLS is more easily oxidized than LS. Based on the excellent electron transporting property of PLS, PLS was applied as a dopant in poly(3,4-ethylenedioxythiophene) (PEDOT, called PEDOT:PLSs). PLS showed excellent dispersion properties for PEDOT. Moreover, the transmittance measurement results showed that the transmittance of PEDOT:PLSs exceeded 85% in the range of 300–800 nm. The CV results showed that the energy levels of PEDOT:PLSs could be flexibly adjusted by PLS amounts. The results indicate that the phenolic hydroxyl group of lignin can be easily boosted by the alkyl chain bridging method, and phenolated lignin-based polymers may have promising potential as dopants of PEDOT to produce hole transporting materials for different organic photovoltaic devices.

关键词: lignosulfonate     phenolic group     PEDOT:PLS     hole extract layer     energy level    

Organic conjugated polymers and polymer dots as photocatalysts for hydrogen production

《能源前沿(英文)》 2021年 第15卷 第1期   页码 667-677 doi: 10.1007/s11708-021-0767-7

摘要: Owing to the outstanding characteristics of tailorable electronic and optical properties, semiconducting polymers have attracted considerable attention in recent years. Among them, organic polymer dots process large breadth of potential synthetic diversity are the representative of photocatalysts for hydrogen production, which presents both an opportunity and a challenge. In this mini-review, first, the organic polymer photocatalysts were introduced. Then, recent reports on polymer dots which showed a superior photocatalytic activity and a robust stability under visible-light irradiation, for hydrogen production were summarized. Finally, challenges and outlook on using organic polymer dots-based photocatalysts from hydrogen production were discussed.

关键词: polymer dots (Pdots)     photocatalysis     hydrogen production    

Construction of interfacial dynamic bonds for high performance lignin/polymer biocomposites

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1372-1388 doi: 10.1007/s11705-023-2302-3

摘要: Lignin is the largest natural aromatic biopolymer, but usually treated as industrial biomass waste. The development of lignin/polymer biocomposites can promote the high value utilization of lignin and the greening of polymers. However, the weak interfacial interaction between industrial lignin and polymer induces poor compatibility and serious agglomeration in polymer owing to the strong intermolecular force of lignin. As such, it is extremely difficult to prepare high performance lignin/polymer biocomposites. Recently, we proposed the strategy of in situ construction of interfacial dynamic bonds in lignin/polymer composites. By taking advantage of the abundant oxygen-containing polar groups of lignin, we inserted dynamic bonding connection such as hydrogen bonds and coordination bonds into the interphase between lignin and the polymer matrix to improve the interfacial interactions. Meanwhile, the natural amphiphilic structure characteristics of lignin were utilized to construct the hierarchical nanophase separation structure in lignin/polymer composites. The persistent problems of poor dispersity and interfacial compatibility of lignin in the polymer matrix were effectively solved. The lignin-modified polymer composites achieved simultaneously enhanced strength and toughness. This concise review systematically summarized the recent research progress of our group toward building high-performance lignin/polymer biocomposites through the design of interfacial dynamic bonds (hydrogen bonds, coordination bonds, and dynamic covalent bonds) between lignin and different polymer systems (polar plastics, rubber, polyurethane, hydrogels, and other polymers). Finally, the future development direction, main challenges, and potential solutions of lignin application in polymers were presented.

关键词: lignin     polymer     interfacial dynamic bonds    

Effect of polymer structures on electro-optical properties of polymer stabilized liquid crystal films

WANG Shoulian, HE Jie, ZENG Yu, YAN Bin, WANG Yinghan

《化学科学与工程前沿(英文)》 2008年 第2卷 第3期   页码 265-268 doi: 10.1007/s11705-008-0054-8

摘要: The polymer stabilized liquid crystal (PSLC) film is a relatively novel electro-optical material, which is generally obtained by dissolving a small amount of a bifunctional photoreactive monomer in a low molecular mass liquid crystal. In this paper, the PSLC films were prepared with photoreactive biphenyl methacrylate monomers by photopolymerization induced phase separation. The effects of liquid crystal concentration, curing time, monomer structures and alignment layer on the electro-optical properties of PSLC films were investigated. The results show that the transmittance in the OFF state () increased with the liquid crystal concentration, but the driving voltage decreased. was also influenced by the curing time. Furthermore, when polyimide was used as alignment layer, the films prepared from the bifunctional monomer shows a higher T, while those from the single functional monomer exhibited a deformed electro-optical curve due to the unsteady polymer networks.

Deformation analysis of shape memory polymer for morphing wing skin under airflow

Weilong YIN, Jingcang LIU, Jinsong LENG,

《机械工程前沿(英文)》 2009年 第4卷 第4期   页码 447-449 doi: 10.1007/s11465-009-0062-5

摘要: The method for analyzing the out-of-plane deformation of a flexible skin under airflow is developed in this paper. The aerodynamic analysis is performed using the CFD software, and the structural analysis is performed using finite element method. The chief aim of the present study is to investigate the out-of-plane deformation of the shape memory polymer (SMP) skin at different temperatures. Numerical results show that the maximum out-of-plane displacement of the SMP skin increases with increasing temperature. When the SMP skin is heated to 53°C, the maximum out-of-plane displacement is about 7 mm. It decreases by 72%, when the SMP skin is applied with a uniform pre-strain of 0.1.

关键词: aircraft     morphing     skin     shape memory polymer (SMP)     deformation     pre-strain    

Fracture model for the prediction of the electrical percolation threshold in CNTs/Polymer composites

Yang SHEN, Pengfei HE, Xiaoying ZHUANG

《结构与土木工程前沿(英文)》 2018年 第12卷 第1期   页码 125-136 doi: 10.1007/s11709-017-0396-8

摘要: In this paper, we propose a 3D stochastic model to predict the percolation threshold and the effective electric conductivity of CNTs/Polymer composites. We consider the tunneling effect in our model so that the unrealistic interpenetration can be avoided in the identification of the conductive paths between the CNTs inside the polymer. The results are shown to be in good agreement with reported experimental data.

关键词: electrical percolation     CNTs/Polymer composites     fracture model     electric conductivity     tunnelling effects    

Preparation and performance of soft actuator based on IPMC with silver electrodes

Qi CHEN, Ke XIONG, Kan BIAN, Ning JIN, Bangfeng WANG,

《机械工程前沿(英文)》 2009年 第4卷 第4期   页码 436-440 doi: 10.1007/s11465-009-0054-5

摘要: The surface electrodes of traditional ionic polymer-metal composites (IPMC) are made of platinum. To reduce the production cost, nonprecious metals such as silver is proposed. A new approach of electroless silver plating based on chemical deposition method is adopted, getting two types of IPMCs, Pt-Ag IPMC, and Ag-Ag IPMC. The microscopic analysis, driving abilities tests, and their surface-electrode resistance analysis show that Ag and Pt particles penetrate inside Nafion membrane with gradient distribution throughout the membrane. The maximum electro-active bending deformation angles of the specimens, which are obtained under the same specimen dimension and constrains, are about 60° for Pt-Pt IPMC and Pt-Ag IPMC and 90° for the Ag-Ag IPMC, respectively, corresponding to the driving voltage of 3 V, 4 V, and 1.5 V. The surface-electrode resistance of Ag-Ag IPMC is the lowest and the most stable, which shows that the proposed approach is valid. The experiments show that the IPMC technology based on the silver electrode is feasible.

关键词: ionic polymer-metal composites (IPMC)     Nafion     intelligent material     soft actuators     electroless silver plating    

标题 作者 时间 类型 操作

Review of recent advances of polymer based dielectrics for high-energy storage in electronic power devices

Wenjie Sun, Jiale Mao, Shuang Wang, Lei Zhang, Yonghong Cheng

期刊论文

Development of electrorheological chip and conducting polymer-based sensor

Xianzhou ZHANG, Weihua LI, Weijia WEN, Yanzhe WU, Gordon WALLACE,

期刊论文

Validation of polymer-based nano-iron oxide in further phosphorus removal from bioeffluent: laboratory

Ming HUA, Lili XIAO, Bingcai PAN, Quanxing ZHANG

期刊论文

Modeling and simulation of droplet translocation and fission by electrowetting-on-dielectrics (EWOD)

Nathan HOWELL, Weihua LI

期刊论文

双氧原子掺杂的氮化硼材料用于吸附脱硫研究

罗静, 魏延臣, 巢艳红, 王超, 李宏平, 熊君, 华明清, 李华明, 朱文帅

期刊论文

Assessing the effects of different dielectrics on environmentally conscious powder-mixed EDM of difficult-to-machine

Jagdeep SINGH,Rajiv Kumar SHARMA

期刊论文

Development of an electrorheological chip and conducting polymer based sensor

Xianzhou ZHANG, Weihua LI, Weijia WEN, Yanzhe WU, Gordon WALLACE,

期刊论文

Numerical modeling of nonlinear deformation of polymer composites based on hyperelastic constitutive

Qingsheng YANG, Fang XU

期刊论文

Lignin-based polymer with high phenolic hydroxyl group content prepared by the alkyl chain bridging method

期刊论文

Organic conjugated polymers and polymer dots as photocatalysts for hydrogen production

期刊论文

Construction of interfacial dynamic bonds for high performance lignin/polymer biocomposites

期刊论文

Effect of polymer structures on electro-optical properties of polymer stabilized liquid crystal films

WANG Shoulian, HE Jie, ZENG Yu, YAN Bin, WANG Yinghan

期刊论文

Deformation analysis of shape memory polymer for morphing wing skin under airflow

Weilong YIN, Jingcang LIU, Jinsong LENG,

期刊论文

Fracture model for the prediction of the electrical percolation threshold in CNTs/Polymer composites

Yang SHEN, Pengfei HE, Xiaoying ZHUANG

期刊论文

Preparation and performance of soft actuator based on IPMC with silver electrodes

Qi CHEN, Ke XIONG, Kan BIAN, Ning JIN, Bangfeng WANG,

期刊论文