Di-block copolymer surfactant study to optimize filler dispersion in high dielectric constant polymer-ceramic composite

Embedded capacitor technology can improve electrical performance and reduce assembly cost compared with traditional discrete capacitor technology. Polymer-ceramic composites have been of great interest as embedded capacitor material because they combine the processability of polymers with the desired electrical properties of ceramics. Dispersion of ceramic particles is a critical factor to affect the effective dielectric constant of polymer-ceramic composite. Di-block copolymer surfactants have been used to prevent agglomeration of the ceramic particles. It was found that di-block copolymer surfactant could improve the ceramic dispersion better than monomer surfactant. Using di-block copolymer surfactant, higher dielectric constant was achieved at lower ceramic loading level. This high dielectric constant polymer-ceramic composite material has much better mechanical properties and can be used for the integral capacitors in the SOP (system on a package) substrate.     

高储能陶瓷/聚偏氟乙烯复合电介质的研究进展

介电电容器作为间歇产生的可持续能源的高效存储转换设备,在新能源领域发挥着不可替代的作用。而电介质电容器的核心是具有高储能密度的电介质材料。聚合物电介质材料由于具有击穿场强高、放电速度快、能长时间使用并可自修复等特点,成为高性能电容器的潜力候选材料,但聚合物本身较低的介电常数限制了其储能密度。通过将具有高介电常数的陶瓷填料与聚偏氟乙烯(PVDF)聚合物复合,制备新型陶瓷/PVDF复合电介质,在提高电介质材料的介电性能和储能密度方面取得了重要进展。本文介绍了电介质材料的基本原理,综述了不同类型的陶瓷/PVDF复合电介质的结构、储能机制及介电储能性能,并对其未来发展趋势进行了展望。      

Dielectric properties of BaTiO<Subscript>3</Subscript>/epoxy composites by lamination process for embedded capacitor application

Because of the fabricability of polymer and excellent dielectric properties of ceramics, ceramic-polymer composites have been investigated widely for embedded capacitors which can improve electric performance greatly. In order to obtain further application of composite, the embedded capacitors with three-layer sandwich structure containing the BaTiO₃/epoxy composites as dielectric layer and copper foil as electrodes were fabricated. The dielectric properties are improved by preventing the defect in dielectric layer through lamination process. Our results show that the capacitors exhibit high dielectric permittivity (ε = 20), low dielectric loss (0.01) at 10³ Hz from 40 to 100 °C and high breakdown strength (24 kV/mm), which indicate that the lamination is a promising process for embedded capacitor fabrication and BaTiO₃/epoxy composites have potential for high-performance embedded capacitors application in field of microelectronics.     

碳纳米管增强聚合物复合材料力学性能及摩擦磨损性能研究进展

本文主要就近几年来碳纳米管、增强聚合物复合材料制备及其力学性能、摩擦磨损性能影响方面研究进展,作一简要介绍.     

纳米陶瓷复合材料进展EI

综述了近年来纳米陶瓷复合材料的研究进展，着重介绍了纳米陶瓷复合材料的制备技术、力学性能的改进情况以及微观结构特点，并提出了关于发展高强韧耐高温纳米陶瓷复合材料的构想。     

Polymer Nanocomposites with Ultrahigh Energy Density and High Discharge Efficiency by Modulating their Nanostructures in Three Dimensions

Manipulating microstructures of composites in three dimensions has been a long standing challenge. An approach is proposed and demonstrated to fabricate artificial nanocomposites by controlling the 3D distribution and orientation of oxide nanoparticles in a polymer matrix. In addition to possessing much enhanced mechanical properties, these nanocomposites can sustain extremely high voltages up to ≈10 kV, exhibiting high dielectric breakdown strength and low leakage current. These nanocomposites show great promise in resolving the paradox between dielectric constant and breakdown strength, leading to ultrahigh electrical energy density (over 2000% higher than that of the bench‐mark polymer dielectrics) and discharge efficiency. This approach opens up a new avenue for the design and modulation of nanocomposites. It is adaptable to the roll‐to‐roll fabrication process and could be employed as a general technique for the mass production of composites with intricate nanostructures, which is otherwise not possible using conventional polymer processing techniques.     

Review Composite and multilayer ferroelectric thin films: processing, properties and applications

This paper reviews recent developments in processing, properties and applications of composite and multilayer ferroelectric thin films. Methods such as physical vapor deposition, chemical vapor deposition and sol-gel, for the processing of composite and multilayer ferroelectric films are described. Among the techniques reviewed for the fabrication of multilayer ferroelectric films, molecular beam epitaxy and atomic layer metal-organic chemical vapor deposition are the most suitable techniques for the deposition of superlattices with atomically sharp interface. As an efficient and quick way, pulsed-laser deposition has been widely used for the preparation of ferroelectric multilayers and heterostructures. Superior dielectric properties have been reported for sol-gel-derived micrometer-thick ceramic/ceramic composite ferroelectric films. Properties of multilayer ferroelectric films vary as a function of periodicity, which can be exploited for the development of various electronic devices. Enhanced characteristics of composite and multilayer films with selected examples from recent literature and the origin of enhancement are discussed and summarized. Finally, applications of the materials for the development of various electronic devices are also presented.     

铁电纳米材料的制备、性能和应用前景

对近年来有关铁电纳米粉体、纳米复合材料、以及纳米陶瓷的制备,结构和性能进行了介绍.对由于粒子尺寸减小引起的结构和性能的改变及其相关机理进行了讨论.透明铁电纳米复合材料可望在光学存储、光学计算等光学器件中得到应用.而纳米陶瓷由于介电特性、耐电压、抗老化、机械强度等性能的提高,因而可以广泛用于改进现有电容器材料的性能,获得性能更加优良的器件.     

Novel Si/cyanate ester nanocomposites with multifunctional properties

Polymer–matrix composites (PMCs) with dispersed Si nanoparticles have been fabricated and investigated for their dielectric and mechanical properties for the first time. It is found that Si nanofillers significantly enhance the dielectric constant of the nanocomposites while preserving the low loss tangent of the Bisphenol E cyanate ester (BECy) matrix. Meanwhile, incorporation of Si nanoparticles effectively stiffens the polymer, as manifested by the large increase in the storage modulus. Furthermore, the AC conductivity of the composite is observed to decrease under compressive mechanical stresses due to the piezoresistive effect of Si. Therefore, these novel Si/BECy nanocomposites simultaneously display mechanical load-carrying, electric energy-storing and stress-sensing capabilities, very promising for multifunctional devices such as structural capacitors.     

Preparation and microwave characterization of BaNd2−xSmxTi4O12 (0 ≤ x ≤ 2) ceramics and their effect on the temperature coefficient of dielectric constant in polytetrafluoroethylene composites

High dielectric and temperature-stable ceramic compositions have been prepared through solid-state ceramic route. The structure and microstructure of the ceramics have been studied using powder X-ray diffraction and scanning electron microscopic techniques. The dielectric properties of well-sintered ceramics are studied in the microwave frequency region using Hakki and Coleman post-resonator technique. The samples exhibited high dielectric constant (>77), relatively high quality factor (>1500) and near zero temperature coefficient of resonant frequency. Phase pure calcined ceramic materials are incorporated in the polytetrafluoroethylene matrix through a proprietary process comprising of sigma mixing, extrusion, calendering followed by hot pressing for the fabrication of planar circuit laminates. The effect of temperature coefficient of dielectric constant of the resultant polytetrafluoroethylene/ceramic composite materials is studied with respect to compositional variation of the filler materials.     

Incorporation of silver nanoparticles coated with mercaptosuccinic acid/poly(ethylene glycol) copolymer into epoxy for enhancement of dielectric properties

A novel route to the synthesis of polymer-coated silver nanoparticles (NPs) was developed on the basis of the reduction of Tollens' reagent using mercaptosuccinic acid/poly(ethylene glycol) (MSA/PEG) copolymer as reducing agent and stabilizer simultaneously. The average size of the polymer-coated silver NPs could be controlled in a wide range from 10 to 120 nm by changing the MSA/PEG molar ratio. These surface-coated silver NPs can be uniformly dispersed in polar solvent and a homogeneous silver NPs/acetone dispersion has been prepared. Silver–epoxy nanocomposites have been developed by incorporating these silver NPs into epoxy. The nanocomposites with silver volume content of 25% showed a more than 3000% increase in dielectric constant as compared to neat matrix and a relatively low dielectric loss below 0.05, which meets the main requirement for embedded decoupling capacitors. Moreover, thermal properties of the silver–epoxy nanocomposites were also characterized by thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMTA). The initial decomposition temperature and glass transition temperature were elevated with the increase of silver content, which exhibit great thermal stability and facilitate electrical applications requiring higher heat-resistance.     

The role of epoxy matrix occlusions within BaTiO3 nanoparticles on the dielectric properties of functionalized BaTiO3/epoxy nanocomposites

In this work, the effects of controlled nanoparticles aggregations of barium titanate (BaTiO₃) on the dielectric properties of epoxy nanocomposites are investigated in detail with respect to different experimental parameters like frequency, ceramic content and temperature. Dispersing silanized BaTiO₃ nanopowder under ultrasonic and stir, nanocomposites of epoxy-amine matrix with different morphologies are obtained. The nanoparticles silane functionalization containing amine end groups effectively improve the compatibility of the nano-BaTiO₃ and the epoxy matrix. Storage modulus, glass transition temperature, tensile and flexural properties of nanocomposites and dielectric properties are increased until 10% by weight of nano-BaTiO₃ loading, well dispersed in the matrix. Above 10 wt.% of nano-BaTiO₃, scanning electronic microscopy and thermal analysis showed that agglomeration of nanoparticles occurs. Rheological and mechanical nanocomposites properties were evaluated and matrix occlusion behaviors were identified. In light of the specific behavior of the occluded polymer, the dielectric properties, especially dielectric loss are discussed.     

Mechanotribological Aspects of MXene-Reinforced Nanocomposites

MXenes are recently discovered 2D nanomaterial with superior mechanical, thermal, and tribological properties, being commonly employed in a wide variety of critical research areas, ranging from cancer therapy to energy and environmental applications. Due to their special properties, such as mechanoceramic nature with excellent mechanical performance, thermal stability and rich surface properties, MXenes have tremendous potential as advanced composite structures, especially those based on polymers due to a great affinity between macromolecules and the terminating groups of 2D MXenes. MXenes have been extensively explored in metal matrix nanocomposites as well as in solid- or liquid-based lubrication systems owing to the 2D structure and antifriction characteristics. The purpose of the this paper is to provide a comprehensive insight into the material, mechanical, and tribological properties of the MXene nanolayers with discussions on the recent advancements attained from MXene-reinforced nanocomposites starting with the synthesis, fabrication techniques, intricacies of the underlying physics and mechanisms, and finally focusing on the progress in computational studies. This analysis of MXene-based composites will stimulate an emerging field with innumerable opportunities and ample potentials to produce newfangled materials and structures with targeted properties.     

Dispersion and functionalization of carbon nanotubes for polymer-based nanocomposites: A review

Carbon nanotubes (CNTs) hold the promise of delivering exceptional mechanical properties and multi-functional characteristics. Ever-increasing interest in applying CNTs in many different fields has led to continued efforts to develop dispersion and functionalization techniques. To employ CNTs as effective reinforcement in polymer nanocomposites, proper dispersion and appropriate interfacial adhesion between the CNTs and polymer matrix have to be guaranteed. This paper reviews the current understanding of CNTs and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT dispersion and functionalization on the properties of CNT/polymer nanocomposites. The fabrication techniques and potential applications of CNT/polymer nanocomposites are also highlighted.     

Flexible Nanodielectric Materials with High Permittivity for Power Energy Storage

Study of flexible nanodielectric materials (FNDMs) with high permittivity is one of the most active academic research areas in advanced functional materials. FNDMs with excellent dielectric properties are demonstrated to show great promise as energy‐storage dielectric layers in high‐performance capacitors. These materials, in common, consist of nanoscale particles dispersed into a flexible polymer matrix so that both the physical/chemical characteristics of the nanoparticles and the interaction between the nanoparticles and the polymers have crucial effects on the microstructures and final properties. This review first outlines the crucial issues in the nanodielectric field and then focuses on recent remarkable research developments in the fabrication of FNDMs with special constitutents, molecular structures, and microstructures. Possible reasons for several persistent issues are analyzed and the general strategies to realize FNDMs with excellent integral properties are summarized. The review further highlights some exciting examples of these FNDMs for power‐energy‐storage applications.     

Polyoxometalate modified inorganic–organic nanocomposite materials for energy storage applications: A review

Modification of organic substrates with inorganic polyoxometalate (POM) clusters can be used to engineer nanocomposite materials with improved properties and diverse functionalities. This review will outline concepts and methodologies for fabricating POM based inorganic–organic composite materials with a special focus on the electrochemical functionality of these composites for energy storage applications. The strengths and limitations of three different fabrication techniques, chemisorption to a carbon surface, immobilization in a polymer matrix, and layer-by-layer self-assembly will be assessed. Furthermore, the latest developments in the use of POM nanocomposite materials in energy storage applications like electrochemical capacitors (ECs) and lithium ion batteries will be presented. This review will highlight the issues and challenges that need to be addressed to achieve inorganic–organic POM nanocomposites able to support high performance energy storage applications.     

Challenges and advances in nanocomposite processing techniques

Of late, nanotechnology seems to be rapidly thrusting its applications in all aspects of life including engineering and medicine. Materials science and engineering has experienced a tremendous growth in the field of nanocomposite development with enhanced chemical, mechanical, and physical properties. A wide array of research has been conducted in the processing of nanocomposites. Consolidation of these systems from loose particles to bulk free form entities has always been a challenge. To name a few, traditional consolidation techniques such as cold pressing and sintering at high temperatures, hot pressing, and hot isostatic pressing have strong limitations of not being able to retain the nanoscale grain size due to the excessive grain growth during processing. This article reviews in detail the results from numerous studies on various methods for manufacturing nanocomposites with improved properties and retained nanostructures. Both challenges and recent advances are discussed in detail in this review.     

Novel Nanoparticle‐Reinforced Metal Matrix Composites with Enhanced Mechanical Properties

This paper summarizes and reviews the state‐of‐the‐art processing methods, structures and mechanical properties of the metal matrix composites reinforced with ceramic nanoparticles. The metal matrices of nanocomposites involved include aluminum and magnesium. The processing approaches for nanocomposites can be classified into ex‐situ and in‐situ synthesis routes. The ex‐situ ceramic nanoparticles are prone to cluster during composite processing and the properties of materials are lower than the theoretical values. Despite the fact of clustering, ex‐situ nanocomposites reinforced with very low loading levels of nanoparticles exhibit higher yield strength and creep resistance than their microcomposite counterparts filled with much higher particulate content. Better dispersion of ceramic nanoparticles in metal matrix can be achieved by using appropriate processing techniques. Consequently, improvements in both the mechanical strength and ductility can be obtained readily in aluminum or magnesium by adding ceramic nanoparticles. Similar beneficial enhancements in mechanical properties are observed for the nanocomposites reinforced with in‐situ nanoparticles.     

聚合物基石墨烯纳米复合材料的研究进展

综述了聚合物基石墨烯及改性石墨烯纳米复合材料的研究进展.添加少量的石墨烯就可以显著提聚合物材料的各方面性能,因此,近年来石墨烯得到了学术界和工业界的高度关注,石墨烯、氧化石墨烯的改性,以及聚合物基石墨烯纳米复合材料被广泛研究.通过广泛的文献阅读对聚合物基石墨烯纳米复合材料的结构、制备方法以及性能进行了深入探讨.     

陶瓷薄膜制备技术研究进展

陶瓷薄膜具有耐磨、耐蚀、耐高温和抗微生物侵蚀等性能,在航天、化工机械、生物医学等行业获得了广泛的应用,从而推动着陶瓷薄膜的材质和制备工艺不断发展.综述了微弧氧化、溶胶凝胶和电泳沉积等制备陶瓷薄膜常用工艺的研究进展,分析了工艺参数对陶瓷膜组织结构和性能的影响.目前,制备工艺正向着电子束、离子束和激光束之间的组合和其工艺间复合的方向发展,陶瓷薄膜正向着多元膜、多层膜、梯度膜和纳米复合膜方向发展.