Direct Ink Writing of Highly Conductive MXene Frames for Tunable Electromagnetic Interference Shielding and Electromagnetic Wave-Induced Thermochromism

The highly integrated and miniaturized next-generation electronic products call for high-performance electromagnetic interference(EMI)shielding materials to assure the normal operation of their closely assembled components.However,the most current techniques are not adequate for the fabrication of shielding materials with programmable structure and controllable shielding efficiency.Herein,we demonstrate the direct ink writing of robust and highly conductive Ti3C2Tx MXene frames with customizable structures by using MXene/AlOOH inks for tunable EMI shielding and electromagnetic wave-induced thermochromism applications.The as-printed frames are reinforced by immersing in AlCl_(3)/HCl solution to remove the electrically insulating AlOOH nanoparticles,as well as cross-link the MXene sheets and fuse the filament interfaces with aluminum ions.After freeze-drying,the resultant robust and porous MXene frames exhibit tunable EMI shielding efficiencies in the range of 25-80 dB with the highest electrical conductivity of 5323 S m−1.Furthermore,an electromagnetic wave-induced thermochromic MXene pattern is assembled by coating and curing with thermochromic polydimethylsiloxane on a printed MXene pattern,and its color can be changed from blue to red under the high-intensity electromagnetic irradiation.This work demonstrates a direct ink printing of customizable EMI frames and patterns for tuning EMI shielding efficiency and visualizing electromagnetic waves.

Synthesis of Cu Nano-particle in Toluene Used for Conductive Ink with a Binder of Polyurethane

Copper nanoparticles with a size of about 150 nm were prepared in toluene using oleic acid as protecting agent. The nanoparticles were used to prepare conductive Cu ink with a polyurethane binder. Oleic acid was used to prevent the nanoparticles from oxidization and agglomeration. The prepared Cu nanoparticles were characterized by X-ray diffraction （XRD） and transmission electron microscopy （TEM）. The resistivity of the copper film on glass substrate that was prepared using Cu nanoparticle ink reached about 1.5× 10-4 2. cm-1 after it was annealed to 120 ~C. Both the nanoparticle ink and the films were characterized by XRD, fourier transform infrared （FT-IR）, and the thermogravimetry-differential scanning calorimetry instrument （TG- DSC）.

Naturally Crosslinked Biocompatible Carbonaceous Liquid Metal Aqueous Ink Printing Wearable Electronics for Multi-Sensing and Energy Harvesting

Achieving flexible electronics with comfort and durability comparable to traditional textiles is one of the ultimate pursuits of smart wearables.Ink printing is desirable for e-textile development using a simple and inexpensive process.However,fabricating high-performance atop textiles with good dispersity,stability,biocompatibility,and wearability for high-resolution,large-scale manufacturing,and practical applications has remained challenging.Here,waterbased multi-walled carbon nanotubes(MWCNTs)-decorated liquid metal(LM)inks are proposed with carbonaceous gallium–indium micro-nanostructure.With the assistance of biopolymers,the sodium alginate-encapsulated LM droplets contain high carboxyl groups which non-covalently crosslink with silk sericin-mediated MWCNTs.E-textile can be prepared subsequently via printing technique and natural waterproof triboelectric coating,enabling good flexibility,hydrophilicity,breathability,wearability,biocompatibility,conductivity,stability,and excellent versatility,without any artificial chemicals.The obtained e-textile can be used in various applications with designable patterns and circuits.Multi-sensing applications of recognizing complex human motions,breathing,phonation,and pressure distribution are demonstrated with repeatable and reliable signals.Self-powered and energy-harvesting capabilities are also presented by driving electronic devices and lighting LEDs.As proof of concept,this work provides new opportunities in a scalable and sustainable way to develop novel wearable electronics and smart clothing for future commercial applications.

Preparation of PDOT:PSS Transparent Conductive Film Using Ink-Jet Printing

Flexible devices produced using organic materials have attracted the attention of many researchers. Important components of these flexible devices include transparent electrodes, which transmit visible light and possess conductivity. The present study improved the characteristics of a transparent conductive film that was made of poly(3, 4 ethylenedioxythiophene):poly(styrenesul-fonate) (PEDOT:PSS), an organic conductive material, and that had been prepared using ink-jet printing. To improve the resistance value and visible light transmittance of the film, the film substrate was first cleaned with ultraviolet/ozone treatment, and then the film was annealed after it was deposited on the substrate and dipped into a polar solvent. Consequently, the resistance value of the thin film decreased. However, the surface state of the film changed according to the treatment method and affected its visible light transmittance. Thus, the surface state of the film substrate, the annealing temperature after film deposition, and the dipping treatment with a polar solvent influenced the characteristics of a thin film.

Investigation of Electrical Stability of Nonwovens with Conductive Circuits Using Printed Conductive Inks

In this work, we study the stability of a class of materials obtained by printing a textile with conductive inks using a method called screen printing. Under the action of a certain external factors, the printed circuit suffers deterioration and the conductivity decreases considerably. In this work, we propose to model the overall damage of the textile sheet in terms of the partial damages of the conductive lines. We also apply this approach to evaluate the damage of a system being made of transmission lines printed into nonwoven substrates using different conductive inks.

Characteristics Improvement of PEDOT:PSS Transparent Conductive Film Prepared by Ink-Jet Printing

Recently, a high-performance and low-priced transparent conductive film has been expected to be developed because flexible devices produced using organic materials have been actively studied. An indium tin oxide (ITO) thin film, which has been generally used as a material for a transparent conductive film, has problems, such as fragility to bending stress and depletion of the resource. The present study used poly(3, 4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS), an organic electroconductive material, and examined the improvement in the resistance value and visible light transmittance of a transparent conductive film produced using the ink-jet method. In previous studies, we reported that, to improve the resistance value and visible light transmittance of a thin film, it was effective to clean the film substrate with ultraviolet/ozone (UV/O3) treatment, anneal the film after it was deposited on the substance, and dip the annealed film into a polar solvent. Focusing on the thin film processing between printing operations, the present study improved resistance value and visible light transmittance by examining both the application methods of a polar solvent and the annealing time between printing operations. As a result, the resistance value and visible light transmittance of a PEDOT:PSS thin film were 390.4 Ω and 86.6%, respectively. This film was obtained by applying a polar solvent and performing annealing for 30 min between printing operations. The printing was performed three times.

Preparation of Cu@Ag Nanoparticles for Conductive Ink

In order to overcome the shortcomings of low-cost anti-oxidation conductive ink and its preparation method in the field of printing electronics, core-shell coated Cu@Ag nanoparticles were used to prepare conductive ink, and a printed circuit was obtained by inkjet printing. Copper nanoparticles were prepared by a chemical reduction method and then coated with Cu@Ag particles by a copper-based self-catalytic reaction. Conductive ink was prepared by ball milling and dispersion and printed on PI film to form a conductive coating. After characterization and analysis, the particle size and dispersion of the obtained Cu@Ag meet the requirements and can be stored stably under normal atmospheric conditions. The resistivity of the conductive film sintered at 300˚C is only 10.6 μΩ∙cm.

无机纳米导电材料在柔性印刷电子中的应用

印刷电子技术起源于可溶液化的有机电子材料,而无机纳米导电材料的兴起推动了印刷电子的快速发展。无机纳米导电材料包括金属、碳材料等导体,以及硅、锗、金属氧化物等半导体。本文概述了无机纳米导电材料在印刷电子领域的发展历程,综述了无机纳米导体材料的性质和油墨化技术,包括可印刷纳米金属材料、碳材料、液态金属以及MXene,并介绍其在柔性与印刷电子领域中的应用。最后指出了可印刷无机纳米导电材料存在的问题及其在柔性与印刷电子领域的发展趋势。

高导电水性石墨烯基导电油墨的制备及其应用性能

为解决柔性电子印刷中传统碳系导电油墨导电性能差的问题,通过引用高导电的石墨烯,制备了基于石墨烯/炭黑/石墨三维导电网络结构的水性石墨烯基导电油墨。探讨了分散剂用量、颜基比和干燥处理工艺三个主要因素对导电油墨导电性能的影响。在此基础上,采用低成本的丝网印刷工艺制备了柔性电热纺织品以评估导电油墨的应用性能。结果表明,制备的导电油墨具有较高的导电性能,最低方阻为20Ω/□。以此制备的柔性电热纺织品具有快速的升温能力和优异的电热稳定性、耐疲劳性,在充电宝5V电压下90s左右可以由室温到达稳态温度(60±3)℃,且具有一定的机械柔韧性。所制备的高导电水性石墨烯基导电油墨在柔性可穿戴领域具有较好的实际应用价值。

基于柔性印刷电路的动态纸媒防伪学习产品探究

为了提高儿童对防伪技术的认知水平,将复杂的防伪技术概念转化为易于理解和吸收的形式,探索并实现一种以纸媒为载体的柔性印刷电路与防伪知识相结合的动态纸媒交互方法。制备了成本低、导电性好、适用于纸基丝网印刷的碳系水性导电油墨,通过学习板、答题纸、知识卡的拼接交互动作,触发柔性印刷电路上的编码点位连通,实现在纸媒实物层面与儿童进行视觉、触觉、听觉的深度交互学习过程。该产品使纸媒与数媒相互融合在一起,共同表达防伪知识的内容并传递给受众,使知识点呈现更加准确、清晰、高效。这种动态纸媒交互方法不仅保留了纸质载体真实自然的教学体验,还通过实体操作充分发挥儿童手、眼、脑的协调作用。同时,以可视化拼接触发编码点位接通的形式让教育大数据有迹可循,进一步推动柔性印刷电路在纸媒创新方面展现出新的活力,更好地传承和发扬中华传统文化的精髓。

纳米银导电油墨及其在柔性印刷电子中的应用

目的探究纳米银导电油墨及其在柔性印刷电子中的应用。方法通过总结国内外文献,从纳米银颗粒及其导电油墨的制备、印刷工艺、烧结工艺以及在柔性印刷电子技术中的应用几方面总结近年来的研究进展。结果在油墨制备及使用中,简化制备工艺、降低生产成本、实现绿色环保、低温烧结,同时提高油墨的基材适应性是未来纳米银导电油墨的改进重点。直写技术具有精度高、速度快等优势,正逐渐替代丝网印刷技术成为主流。烧结工艺的研究重点在于实现低温烧结,其中化学烧结工艺简单,但提高导电性是研究重点。其他烧结方式则设备昂贵,环境要求高。结论作为功能性电子材料,纳米银导电油墨因出色的电性能和印刷适性,正在被广泛应用于柔性印刷电子中。近年来通过对纳米银及其导电油墨的深入研究及技术改进,在纳米银颗粒的制备、低温烧结技术、节能环保加工工艺等方面获得了一定的进展。与此同时,将其作为功能材料应用于制备柔性传感器中,RFID标签天线、柔性电极、超级电容器、太阳能电池等正受到广泛研究与应用。

导电油墨印刷制程与电阻的关系

柔性电路印刷的制程会导致电阻的变化,印刷后的电路会因为使用环境的变化等因素影响电阻波动的设计率标。以网印工艺法和银介质的导电油墨为例,从印刷制程和印后环境两个部分,分享导电油墨的电阻方案。

Influence of co-solvent hydroxyl group number on properties of water-based conductive carbon pastes

A series of water-based conductive carbon pastes were prepared by wet ball milling, followed by vacuum defoaming using isopropyl alcohol, propylene glycol or glycerin as co-solvents. Screen printing was then used to prepare conductive patterns. To determine the influence of co-solvent hydroxyl group number on the properties of water-based conductive carbon pastes, the rheological properties of the pastes and the surface morphologies and conductivities of the printed patterns were characterized. The results show that paste viscosity increased with the number of hydroxyl groups and the latter also affected thixotropy. In addition, the boiling points and surface tensions of the co-solvents increased consistently with hydroxyl group number, affecting the hydrodynamic flow. The conductive carbon paste created using propylene glycol as a co-solvent was the best for screen printing because of its weak coffee-ring effect and appro- priate rheological properties, resulting in a smooth coating surface and uniform deposition of the fillers. The resistivity of the pattern printed using paste PG, containing the closest packing of conductive carbon black particles, was 0.44 Ω cm.

碳系导电油墨的导电性能研究

将碳纳米管作为导电填料,加入喷墨打印专用墨水,制备成新型碳系导电油墨,并加入助剂等添加剂调节油墨的综合性能。通过实验,研究分析了碳系导电油墨中碳纳米管的质量分数、形成碳系导电油墨涂层的喷涂层数,油墨涂层喷涂成型后的静置时间、电极铜片与油墨涂层的接触面积、油墨涂层的基底材料等对其导电性能的影响。结果表明,碳系导电油墨的电阻随着碳纳米管质量分数和喷涂层数的增加而下降;一定质量分数的碳系导电油墨,喷涂3层以上时,涂层电阻对喷涂完成后的静置时间效应不敏感;对于一定特性的碳系导电油墨涂层,总电阻值与接触面积的倒数值具有线性关系;不同的涂层基底材料对导电涂层的导电性能有影响。

基于3D打印构筑的高面间热导率氮化硼陶瓷的制备

氮化硼(BN)陶瓷具有高纵横比、耐高温、高导热和电绝缘性等优异性能,广泛应用于电子信息、航天航空、冶金、机械等领域。3D打印技术与传统加工方式相比具有低成本和省时等特点,是制备具有复杂三维结构陶瓷制件的重要成型技术。为此,基于自主研发的气压式新型直写3D打印材料成型平台,使用BN和聚乙烯醇(PVA)作为原料和粘结剂,制备了不同BN含量的陶瓷浆料,利用逐层堆积原理,设计并制备具有不同三维结构的陶瓷预制件,通过改变浆料的流变学特性,在打印过程中实现了BN二维纳米片在剪切力作用下的取向,得到了高面间热导率的陶瓷材料。研究了BN含量对陶瓷制件成型质量的影响,并且采用了XRD和SEM对打印得到的陶瓷材料的结构和微观形貌进行了表征。结果表明,BN/PVA 85浆料有着良好的剪切变稀特性和黏弹性,在线性黏弹性区的屈服应力达到240 Pa,适配于直写成型3D打印技术。BN在制件内部的水平取向度提高有助于增强陶瓷材料的面间热导率,其中,BN/PVA 85陶瓷制件的面间热导率约为4.3 W/(m·K)。

酰胺化氮化硼−氧化石墨烯导热绝缘油墨的研制

目的研制兼具导热和绝缘特性的油墨,以拓展油墨在电子器件领域的应用。方法以氮化硼(BN)晶体和尿素为原料,采用球磨法合成了氨基化氮化硼(BN−NH_(2))纳米片,并在羧基活化剂的参与下,利用氧化石墨烯(GO)上的羧基与BN−NH_(2)上的氨基共价反应,制备酰胺化氮化硼−氧化石墨烯纳米复合填料(BN−GO),辅以高分子树脂、单体、颜料及各类助剂,研制导热绝缘油墨。利用扫描电子显微镜、X射线衍射仪、激光拉曼光谱仪、傅里叶变换红外光谱仪和X射线光电子能谱仪等手段对BN−NH_(2)纳米片的形貌结构、晶型晶面和BN−GO的价键结构进行表征,最后对油墨的印刷适性、导热性能和绝缘性能进行测试。结果实验成功制备了氨基化氮化硼(BN−NH_(2))纳米片和酰胺化氮化硼−氧化石墨烯纳米复合填料(BN−GO),当BN−GO的质量分数为3.0%时,所制备的导热绝缘油墨的印刷适性良好,印刷打样后的导热系数可提升至1.45 W/(m·K),体积电阻率高达9.86×10^(11)Ω·cm,相较于空白油墨试样,分别提升了4.8倍和3.7倍。结论所研制导热绝缘油墨可在保持良好印刷适性的同时赋予油墨优良的导热性能。

生态导电油墨及其在包装领域的应用研究进展

导电油墨的制备已成为加快印刷电子发展的重要技术之一,近年来符合生态理念的导电油墨逐渐成为研究热点。通过对生态导电油墨的相关文献进行分析与梳理,综述了生态导电油墨的研究现状、导电机理和应用方向。归纳出生态导电油墨主要可分为溶剂型和能量固化型两类,总结了生态导电油墨在智能包装中的应用,如:印刷柔性电池、电子交互包装、RFID标签、薄膜开关等,此类产品为包装在智能交互、信息追踪溯源、防伪防盗等方面提供强力的技术支持。

柔性织物压力传感器的制备及其性能研究

为改善基于织物的柔性可穿戴压力传感器在使用时的灵敏度、可靠性和可持续性,采用直写工艺设计和制作纳米银线叉指电极,并将其作为底电极;采用浸泡工艺制作纳米银线导电织物,将其作为压阻层。将两者组装成为压阻式柔性织物压力传感器,并测试相关性能。结果表明:施加不同的压力,压力传感织物的电流都是随着施加电压的增加而线性增加;压力传感织物具有较好的传感稳定性和重现性,对外力具有较好的响应性能和较高的灵敏度;柔性织物压力传感器在0.1 V的低电压下实现了出色的开关比,5 g砝码压力下快速响应性能较好。认为:制备的柔性压力传感器在可穿戴控制器和运动检测中具有潜在应用价值。

直写成型刚玉-莫来石质多孔材料研究

以d_(50)=10.3μm的烧结刚玉微粉、d_(50)=0.2μm的SiO_(2)微粉和化学纯六偏磷酸钠为主要原料,按m(烧结刚玉微粉)∶m(SiO_(2)微粉)=11∶1,每100 g烧结刚玉微粉添加0.15 g六偏磷酸钠的配比配制固含量为63%(φ)的浆料,经真空消泡处理后,采用直写成型技术打印出孔的横截面分别为正三角形、正方形、正六边形的直通孔型多孔材料,研究了孔形、孔径以及受力方向和传热方向对材料常温耐压强度和热导率的影响。结果表明:1)打印出的多孔材料均未出现肉眼可见的缺陷或变形,表面较为光滑平整,挤出线条均匀流畅;打印层间接触紧密,未见分层现象。2)在孔隙率相同时,材料的常温耐压强度按正三角形孔材料、正方形孔材料、正六边形孔材料的顺序逐渐增大,热导率则按此顺序逐渐减小。3)在孔形和孔隙率相同时,材料的常温耐压强度随孔径的增大而减小,热导率则随孔径的增大而增大;在孔形、孔径和孔隙率相同时,平行于直通孔方向的常温耐压强度和热导率大于垂直于直通孔方向上的常温耐压强度和热导率。

纳米甲壳素基导电墨水的制备及在苯二酚快速检测上的应用

纳米甲壳素(ChNCs)绿色环保,具有良好的生物相容性,在智能响应、电子传感及生物医疗领域的应用潜力巨大。本研究首先通过碱处理的方法从蟹壳中提取ChNCs,然后将多壁碳纳米管(MWCNT)分散其中,以制备符合书写要求的导电墨水。该生物质墨水性质稳定,拥有良好的流变与电学性能,可以填充在滚珠笔中绘制苯二酚检测传感器。测试结果表明,通过此方法构建的电化学传感器对三种苯二酚(DHB)异构体具有电分离作用,使用差分脉冲法(DPV)同时定量检测对苯二酚(HQ)、邻苯二酚(CC)与间苯二酚(RC),检出限分别为4.2×10^(-5)mol/L、3.2×10^(-5)mol/L、3.0×10^(-5)mol/L,满足国家标准HQ类物质的环境监测要求。