Control of the Surface Morphology of Ceramic/Polymer Composite Inks for Inkjet Printing

The use of organic/inorganic composite inks in the Drop on Demand inkjet printing technology is a promising as well as demanding approach for the fabrication of composite thick films. Therefore, a versatile ceramic/polymer composite ink system for inkjet printing is developed in this study, containing Ba_0.6Sr_0.4TiO₃ (BST) and poly(methyl methacrylate) (PMMA). When developing such inks suitable for a one‐step fabrication, the major challenge is to fulfill the requirements of the inkjet printing technology and to obtain homogeneous surface morphologies after drying. Thus, possible influencing factors like the solvent composition, the solids content, and the ratio of ceramic to polymer are investigated to obtain a detailed knowledge for the general ink development. The fluid mechanical properties, viscosity, density, and surface tension are characterized. The main focus of this study lies on the drying behavior of the different inks, with the interactions of the ceramic particles, and the dissolved polymer molecules being highlighted. Furthermore, the drying behavior depending on the ink composition is shown. This study provides new insights into the possibility of using composite inks for the inkjet printing process and the fabrication of printed composite thick films in a single process step.

     

聚合物/无机复合材料在介电材料领域的应用

综述了传统聚合物／无机杂化材料在介电材料领域应用的最新进展，以及聚合物／无机纳米复合材料作为介电材料应用的进展，特别是复合材料作为高储能、高介电强度、低损耗介电材料的研究进展和前景。     

BST/PVDF复合薄膜的制备及其介电性能

以溶胶-凝胶法制备出钛酸锶钡(Ba0.65Sr0.35TiO3)粉体,并对粉体进行表面改性处理,然后将处理和未处理的粉体按不同的比例与聚偏氟乙烯(PVDF)进行复合,用甩胶法做成薄膜样品,对样品进行了介电性能的测试.实验结果表明:复合薄膜的介电常数实测值与理论值符合得较好,随着薄膜中BST粉体比例的增加,复合薄膜的介电常数和介电损耗增大;经表面改性后的BST粉体所制备的复合薄膜与未经改性所制备的薄膜相比,介电常数略有上升,而介电损耗显著下降.     

喷墨打印量子点薄膜制备的影响因素研究

目的 为了通过喷墨打印技术很好地实现量子点薄膜图案化,需要调节量子点薄膜制备工艺的各项参数以获得表面均匀、厚度适宜和无咖啡环结构的量子点薄膜。方法 基板和退火是影响量子点薄膜成膜性能的2个重要参数,分别研究基板的清洗、材料和温度以及退火的温度和时间对喷墨打印量子点薄膜成膜性能的影响。结果 选择3种不同类型的溶剂依次清洗可提高基板表面能,有利于墨水的铺展;PVK基板的量子点面薄膜形貌相较于Pedot:Pss更均匀;当基板温度为50 ℃、退火温度为80 ℃或90 ℃、退火时间为15 min时,咖啡环效应最弱,可获得表面均匀、厚度适宜和无咖啡环结构的量子点薄膜。结论 基板的清洗、自身材料以及温度都会影响墨水的铺展性能,从而影响量子点薄膜的成膜性能;控制退火温度与退火时间,以使马兰戈尼流起作用,咖啡环效应被明显抑制,可以获得表面均匀的量子点薄膜。     

Low Loss Sintered Dielectric Resonators with HTS Thick Films

The combination of high-Qdielectric resonators and high-temperature superconducting (HTS) films offer many advantages in the area of cellular and satellite communications. The high cost of single crystal dielectrics and HTS thin films may be unattractive in certain applications. Superconducting thick films and polycrystalline ceramic dielectrics offer a high performance, low-cost alternative to high-Qthin film/single crystal dielectric resonators. The loss of polycrystalline ceramics of A1₂O₃, Ba(Mg_1/3Ta_2/3)O₃ (BMT), and Zr_0.875 Sn_0.25Ti0.875O₄ (ZTS) has been studied. Alumina, A1_2Oin3, has been studied as a model material for dielectric loss. Theory predicts that the loss in single crystal sapphire should follow aT ₅ dependence. However, at low temperatures the loss is dominated by extrinsic losses due to crystal imperfection, residual dopant atoms, dislocations, and other lattice defects and theT ₅ dependence does not hold. In polycrystalline alumina the intrinsic loss is immediately masked by these extrinsic losses, even at room temperature, and a simpleT dependence is observed. Results on polycrystalline alumina show that Q’s well in excess of 105 at 10 GHz and 77 K can be achieved in a design made compact by the use of a HTS thick film shield.     

喷墨打印技术概述

本文较系统地介绍了热泡喷墨、压电连续喷墨和压电按需喷墨等三种喷墨打印技术，较详细地阐述了它们的技术原理、技术特点、优缺点和主要应用厂家。     

墨水直写、喷墨打印和激光直写技术及其在微电子器件中的应用

直写技术是一种新型微加工技术,其加工过程不需模板并可在亚微米至厘米范围实现材料加工成型。墨水直写、喷墨打印和激光直写作为最常用的直写技术,具有强大的二维、三维成型能力和优异的成型精度,可实现金属、陶瓷、聚合物、水凝胶等复杂构型的程序化构筑,被广泛应用于微电子、组织工程、微流控等领域。阐述了这3种直写技术的构型原理和材料选择,重点介绍了其在微电子器件制造中的应用,讨论了当前研究的难点和热点问题,并对其未来发展趋势进行了展望。     

墨水直写、喷墨打印和激光直写技术及其在微电子器件中的应用

直写技术是一种新型微加工技术,其加工过程不需模板并可在亚微米至厘米范围实现材料加工成型.墨水直写、喷墨打印和激光直写作为最常用的直写技术,具有强大的二维、三维成型能力和优异的成型精度,可实现金属、陶瓷、聚合物、水凝胶等复杂构型的程序化构筑,被广泛应用于微电子、组织工程、微流控等领域.阐述了这3种直写技术的构型原理和材料选择,重点介绍了其在微电子器件制造中的应用,讨论了当前研究的难点和热点问题,并对其未来发展趋势进行了展望.     

Enhanced Dielectric Performance in Polymer Composite Films with Carbon Nanotube‐Reduced Graphene Oxide Hybrid Filler

The electrical conductivity and the specific surface area of conductive fillers in conductor‐insulator composite films can drastically improve the dielectric performance of those films through changing their polarization density by interfacial polarization. We have made a polymer composite film with a hybrid conductive filler material made of carbon nanotubes grown onto reduced graphene oxide platelets (rG‐O/CNT). We report the effect of the rG‐O/CNT hybrid filler on the dielectric performance of the composite film. The composite film had a dielectric constant of 32 with a dielectric loss of 0.051 at 0.062 wt% rG‐O/CNT filler and 100 Hz, while the neat polymer film gave a dielectric constant of 15 with a dielectric loss of 0.036. This is attributed to the increased electrical conductivity and specific surface area of the rG‐O/CNT hybrid filler, which results in an increase in interfacial polarization density between the hybrid filler and the polymer.     

Electrochemical Formation of Polypyrrole-carboxymethylcellulose Conducting Polymer Composite Films

1.IntroductionConjugated polymers such as polypyrrole(PPY),polyaniline,polythiophene and polyphenylene etc.whichexhibit significant level of electrical conductivity andhence are termed as conducting polymers,have gotversatile promising applications in the field of energystorage[1],sensors[2],electronic and optical devices[3]andso on.Many researches have been conducted to pro-duce composites or blends of conducting polymer filmswith some insulating polymers in order to overcome thedrawbacks su…     

喷墨印刷液滴的铺展特性研究

目的 研究喷墨印刷液滴相关参数对其铺展特性的影响,为喷墨印刷质量的研究奠定基础。方法 采用Fluent软件,基于VOF(Volume of Fluid)法,建立液滴撞击光滑承印物表面并铺展的仿真模型,采用PISO(Pressure-Implicit with Splitting of Operators)算法对速度和压力进行耦合,分析液滴相关参数对其撞击铺展的影响规律。结果 当液滴飞行速度为6 m/s、接触角度为40°、液滴流体黏度为0.005 Pa.s、液滴直径为0.08 mm时,液滴撞击光滑承印物表面的铺展系数最大,铺展程度最好,铺展特性最优。结论 铺展系数随液滴直径、流体黏度和接触角的增大而降低,随飞行速度的增大而增大。     

铝/改性氟塑料复合薄膜的制备

采用射频磁控溅射技术在改性氟塑料表面沉积铝层,制备了金属/氟化高聚物复合薄膜.利用场发射扫描电镜(FESEM)及能量散射谱(EDS)分析仪对沉积的铝层进行了表面形貌的表征和化学组分的分析.初步探讨了溅射功率、气压和时间等不同溅射参数对铝层结构和铝层在氟塑料表面附着情况的影响.结果表明:溅射功率是决定复合薄膜质量的重要因素,功率过低得不到致密的铝层结构,而且铝层容易从氟塑料表面脱离,功率过高则会产生很强的热效应而使复合薄膜弯曲.溅射气压和时间分别影响铝层在氟塑料表面的沉积速率和生长厚度.