一步法制备明胶-阿拉伯树胶电子墨水微胶囊

采用硬脂酸对TiO2纳米颗粒进行表面改性处理,以明胶-阿拉伯树胶为壁材,通过 一步复凝聚法制备了白色电子墨水微胶囊.傅立叶变换红外光谱仪及动态光散射仪分析表明,改性后的TiO2在四氯乙烯中具有良好的分散性.对分散体系进行微胶囊化处理后,颗粒能够均匀而稳定地分布在微胶囊内.调节明胶-阿拉伯胶用量、滴酸速度及浓度等,获得了无粘连、囊壁光滑、厚度可控的微胶囊.在10 V/靘的直流电场作用下,胶囊内改性TiO2纳米颗粒表现出良好的电场响应可逆移动特征.     

工艺参数对可逆示温微胶囊性能影响的研究

以乙基纤维素和聚乙烯为壳材料,热敏变色材料氯化钴为芯材料,Span80为乳化剂,采用油相分离法,对热敏变色材料氯化钴进行高分子材料包覆,制备了polyethylene/ethyl cellulose(PE/EC)可逆示温微胶囊.研究了壳材料用量、乳化剂用量、搅拌速率、相分离时间和环己烷用量等工艺参数对微胶囊的形成状态、包裹率等的影响规律,研究结果表明,工艺参数对微胶囊的变色温度影响不显著;随着相分离时间的增加,微胶囊的包裹率增大;随着搅拌速率的增加,微胶囊的包裹率呈先增大再降低的趋势.利用扫描电镜(SEM)和光学显微镜(OM)进行表征.微胶囊化的最佳试验条件为核壳比为1∶1, 相分离时间为3 h～4 h,搅拌速率为900 r/min.所制备的微胶囊极大地提高了可逆示温材料的变色灵敏性、环境适应性与高分子材料的相容性,具有良好的应用前景.     

可逆示温微胶囊的制备及性能研究

采用油相分离法,以示温变色材料CoCl2·6H2O为芯材料,乙基纤维素、聚乙烯为壳材料,Span80为乳化剂,环己烷(HC)为溶剂,制备了可逆示温微胶囊.利用扫描电子显微镜、光学显微镜和热台偏光显微镜对可逆示温微胶囊进行了结构表征与性能分析,对所制备可逆示温微胶囊材料的耐疲劳性、耐溶剂性以及与高分子材料的相容性进行了研究,并重点就可逆示温微胶囊在油墨中的制备工艺、对油墨性能的影响进行了深入的研究与讨论.结果表明,所制备的微胶囊粒径均匀,平均粒径为4.5 μm.所制备的可逆示温丝网油墨具有优良的性能.     

微胶囊相变材料制备条件的优化

考察了乳化剂用量和搅拌速度对微胶囊相变材料制备的影响,通过测试证明：当乳化剂用量为9.4~9.8mL,搅拌速度为300r/min时,在三聚氰胺：甲醛=1：2.5,石蜡为10g,温度为80℃的条件下,制备得到的微胶囊相变材料包膜性能和分散性能较好。     

金红石型纳米TiO2粉体的制备及其分散

为使金红石型纳米TiO2在水溶液中良好稳定地分散,采用Ti(SO4)2水热合成法,在低温下制备了纳米TiO2粉体,并选取几种无机、有机分散剂对合成的TiO2在水中的分散行为进行了比较。XRD图谱显示,合成的TiO2为金红石型;TEM照片表明,TiO2颗粒粒径在100nm左右,且基本为球状颗粒;分散测试得出以质量比为1:1混合的三聚磷酸钠和1631作为复合分散剂具有最佳的分散效果,分散率在70%左右。     

黄绿电子墨水微胶囊的制备及性能研究

利用十八胺改性的酞菁绿G作为绿色显示颗粒,span80为电荷控制剂,四氯乙烯为分散介质,油溶黄为背景色,制备稳定的电泳液,采用界面聚合法制备出电子墨水微胶囊。研究了改性后的酞菁绿G颗粒在电泳液中分散性和颗粒大小分布,通过SEM照片证明,当十八胺的质量分数为4%时,酞青绿G在四氯乙烯下分散效果最好。对电泳液进行微胶囊化处理后,在E=50V/mm电场下,微胶囊中的颗粒可以进行可逆运动。     

Pechini溶胶-凝胶法制备电子墨水用TiO2白色显色颗粒

采用Pechini溶胶-凝胶法制备出了适于电子墨水用的实心球形TiO2白色显色颗粒,颗粒粒度约为300 nm。采用热重-差热、X射线衍射、扫描电子显微镜等分析方法,研究了前驱物的组成对所得颗粒的形貌、粒径和分散程度的影响规律以及TiO2颗粒的晶相转变温度。研究表明:络合物经过煅烧,在500℃时开始出现锐钛矿相TiO2,800℃时由锐钛矿相向金红石相转变;不同条件下制备的TiO2均为球形颗粒,TiO2颗粒的粒径随Ti(SO4)2浓度的增大而增大,当柠檬酸的质量分数为12%时,TiO2颗粒的粒径有最小值。     

PMOCOPV/TiO2纳米复合材料的制备及发光性能

采用原位聚合方法制备聚(2-甲氧基-5-辛氧基)对苯乙炔(PMOCOPV)/二氧化钛(TiO2)纳米复合材料.利用傅里叶变换红外光谱(FT-IR)、紫外-可见吸收光谱(UV-Vis)、透射电镜(TEM)和荧光光谱(FL)对纳米复合材料的结构及发光性能进行研究.TEM显示,纳米复合材料为分散均匀的球形颗粒,粒径尺寸为60～80 nm.PL谱表明,随着TiO2含量增加,纳米复合材料的发光强度逐渐增强,且发射峰由600nm蓝移至575 nm.     

TiO2含量对PTFE/TiO2微波介质复合材料性能的影响

采用机械搅拌、冷压成型和烧结相结合的方法制备了TiO2填充聚四氟乙烯(PTFE)微波介质复合材料,通过扫描电镜表征了TiO2颗粒存PTFE中的分散情况及复合材料的微观形貌,测定了材料的热膨胀系数、介电性能及吸水率等参数.重点研究了不同含量TiO2对复合材料热、介电性能的影响.结果表明,随着TiO2含量的增加,复合介质板的密度先增大到一个最大值然后减小,吸水率、介电常数和介电损耗随着TiO2含量的增加而增加,热膨胀系数则呈相反趋势.TiO2含量增加约65％时,复合材料的密度达到最大值(2.802 g/cm3),此时介电常数为8.89,介电损耗为0.002 5.     

蓝色电子墨水微胶囊的制备及其电场响应行为

利用脲甲醛树脂为壁材制备了以酞菁蓝BGS(β-CuPc)颗粒分散在四氯乙烯(TCE)中的悬浮液为核材料的蓝色电子墨水微胶囊。研究了不同改性剂与表面活性剂对β-CuPc颗粒的改性效果及在TCE中的分散性、TCE／水界面张力及囊内β-CuPc微颗粒在胶囊内表面的吸附的影响。结果表明，用十八胺(ODA)改性的β-CuPc颗粒在TCE中的分散性有很大程度提高，其电泳移动速度是未改性前的20倍；TCE／水间的界面张力越大越有利于微胶囊的形成；在TCE中的油溶性表面活性剂Span-80的浓度不低于0．062mmol／L时，β-CuPc颗粒在胶囊内表面吸附被阻止。在100V／mm的直流电场下．微胶囊囊内TCE中分散的β-CuPc颗粒表现出良好的可逆移动特征。     

Effects of the ink concentration on multi-layer gravure-printed PEDOT:PSS

To date, highly conductive PEDOT:PSS is the most promising transparent electrode for printing-based flexible organic electronics. Spin-coating and slot-die coating have been commonly used for printing this material. Among the roll-to-roll printing processes, gravure is the most promising for manufacturing large area electronics offering the advantages of high speed and high printing definition. However, gravure printing highly conductive PEDOT encounters some technological limitations such as low thickness, layer inhomogeneity and high surface roughness resulting in a layer not suitable as electrode in electronic devices. In order to realize an electrode of highly conductive PEDOT by gravure printing, a multilayer approach with variable ink concentration was tried using IPA as process solvent. Variable solvent amount of overlapped printed layers was found to play an important role in the spreading of the PEDOT ink onto the pre-printed layers and in the smoothing of its existent peaks. In particular, adopting increasing ink dilution with increasing of the overlapped layers, multi-layer gravure-printed highly conductive PEDOT was successfully realized with characteristics suitable as transparent electrode for organic electronic devices (sheet resistance lower than 130 Ω/sq, conductivity higher than 450 S/cm and optical transmittance over 80%). This is the first time that such results were reached by gravure printing technique thanks to the easy proposed approach.     

二硫化钼纳米薄片分散液的剥离制备

文中采用液相超声剥离粉末二硫化钼制备了纳米薄片分散液,通过紫外可见吸收光谱测定分散液的浓度,并探索了超声功率、超声时间以及二硫化钼初始浓度对纳米薄片分散液浓度的影响。实验结果表明,当超声功率为350 W,超声时间为48 h,二硫化钼初始浓度为10 mg/mL时,所制备的纳米薄片分散液浓度可达0.16 mg/mL。在剥离过程中加入聚乙烯吡咯烷酮,可以有效避免由于纳米薄片自身团聚而导致的分散液稳定性差的问题,所得到的二硫化钼纳米薄片分散液可稳定存放超过两个月;同时,PVP的加入可将二硫化钼纳米薄片分散液浓度提高至0.42 mg/mL。     

纳米Ag-Cu-In-Sn合金粉体的分散稳定性研究

通过等离子体蒸发凝聚法制备纳米Ag-Cu—In—Sn合金粉，初步研究了聚乙烯吡略烷酮K-30（PVP）和十六烷基三甲基溴化铵（CTAB）及其分散工艺对合金粉体分散性能的影响。研究结果表明：随着超声时间的增加，吸光率增大，分散性能变好；与CTAB相比PVP的分散效果更好，其最佳分散浓度为1．8g／L。     

一种新型电子标签天线用导电油墨的配制

基于电子标签天线对导电性要求较高的特性,实验以自制Ag作为导电填料。论文采用液相化学还原法,以次磷酸钠为还原剂,还原硝酸银制备纳米银胶。通过控制反应条件(温度、pH值等)、反应物的量(六偏磷酸钠、PVP),制备出粒径分布均匀、分散稳定性优良的纳米银胶。通过向银胶中添加电解质,析出纳米银粉,加上适量的助剂、溶剂和分散剂,制备了水性丙烯酸树脂和水性聚氨酯基导电油墨。分析了影响油墨导电性能的各影响因素。     

Magnetochromatic Microcapsule Arrays for Displays

An approach to construct displays based on magnetochromatic microcapsules with narrow size distribution has been proposed. These magnetochromatic microcapsules are fabricated by a microfluidic technology. The shell layer of the obtained microcapsule is composed of transparent photocurable ethoxylated trimethylolpropane triacrylate (ETPTA) resin while the core is formed by the aqueous droplet containing monodisperse magnetic nanospheres. The capsule size, shell thickness, and morphology can be easily controlled by the flow rates during the fabrication. In the multipixel array formed by these microcapsules, each microcapsule acts as an individual display unit. The nanospheres in the core droplet can be influenced by an external magnetic field, forming ordered structures which determine light diffraction; therefore, various distinct colors are observed according to the intensity of the external magnetic field. These microcapsules have the advantage of long time stability, viewing angle independence, and dynamic tunable optics.     

Characteristics of eco-friendly synthesized SiO2 dielectric nanoparticles printed on Si substrate

We developed an eco-friendly method for manufacturing SiO₂ nanoparticles and, thereby, SiO₂ ink to be used in the digital printing process for the fabrication of SiO₂ film. The synthesized SiO₂ nanoparticles were dispersed in an organic solvent with additives to make a SiO₂ ink for feasibility testing. For the dispersion of the nanoparticles, two kinds of dispersing agents were employed and compared, e.g., Polyvinylpyrrolidone (PVP) and hydroxypropylcellulose (HPC). From the dispersion testing with the two agents, the HPC was considered to be more suitable for the dispersion of the SiO₂ nanoparticles synthesized in this study. Then, an attempt was made to fabricate a printed SiO₂ film on a Si substrate to see whether the SiO₂ nanoparticles can be used for printing or not. The insulation resistance and dielectric constant of the SiO₂ powders were also measured and found to be reasonable for the use as an insulation layer for passivation. Finally, the electrical losses were measured under high frequencies to evaluate the feasibility of the SiO₂ ink for various high frequency applications.     

The absorption ink transfer mechanism of gravure offset printing for electronic circuitry

The gravure offset method has been developed toward an industrially viable printing technique for electronic circuitry. In order to obtain the optimum ink resin for printing lines of required thickness (>5 /spl mu/m) of narrow lines (down to 25 /spl mu/m), several ink resin systems have been assessed in previous studies by the authors. The best printed results were obtained with a novel ink using a hydrocarbon resin. This ink did not comply with the traditional ink transfer mechanism based on evaporation of the solvent, but with a postulated new "absorption mechanism.".     

Significant effect of the molecular formula in silver nanoparticle ink to the characteristics of fully gravure-printed carbon nanotube thin-film transistors on flexible polymer substrate

Single-walled carbon nanotubes (SWNTs) are a valuable material for use in not only nanoelectronics but also printed electronics because of their stability, tunable operation speed, and scalability. However, the device characteristics of fully printed, SWNT-based thin film transistors (SWNT-TFTs) often have large variations, and the fundamental cause of these inconsistencies are not yet well understood. Therefore, fully printed SWNT-TFT-based electronic devices have not been practically realized in the market. In this study, the significant variation in the electrical parameters of printed SWNT-TFTs that is caused by minor molecular variations in the formulation of silver nanoparticle-based ink is reported. Strikingly, a very small difference in the chemical structure between ethylene glycol and diethylene glycol in the silver nanoparticle-based ink, which is used to print drain-source electrodes in the SWNT-TFTs, with everything else identical, induced a difference of approximately 70 meV in the barrier height between the drain-source electrodes and the SWNT layer at 300 K. The modification of the absorbed polymer binder in the silver nanoparticle ink due to the additive is the major cause of the observed barrier height difference. These results allow for a better understanding of the relationship between the ink rheology at the molecular level and the printed device properties, and enable a more precise design and control of device properties which will have profound impacts on printed electronic devices.     

Room Temperature Dielectric Pulse Effect in Organic Mixtures

The dielectric pulse effect is of interest for many applications such as sensors, smart triggers, and energy storage. In this paper, a general approach to achieve a room temperature dielectric pulse effect via solid–liquid phase transition in organic mixtures formed by conductive surfactants and insulating fluid is introduced. The dielectric pulse is caused by the self‐formed blocking layer appearing during the solid–liquid phase transition by mixing Span80 and hexadecane. Using 50 Vol% Span80/hexadecane mixture, the dielectric peak intensity of 1191.6 is achieved at 11.9 °C. The dielectric peak intensity and the trigger temperature of mixtures can be tuned by changing the proportions of the components, the temperature ramping rate, and the components. The generality of the approach is also demonstrated in other organic matter such as Span series, alcohols, alkanes and their mixtures.