表面活性剂结构对纳米CeO2在水中的分散性影响

采用悬浮液体系吸光度法,研究不同结构表面活性剂对纳米CeO2粉体在水中分散性影响。考察了影响分散稳定性的物理分散方式、表面活性剂的结构和浓度等因素。结果表明,超声波分散效率远优于机械搅拌。表面活性剂作为纳米CeO2在水介质中的分散剂,其分散性与表面活性剂结构有重要关系。非离子型表面活性剂效果优于离子型表面活性剂。非离子型表面活性剂以亲油基团朝向CeO2粒子,且亲油基团链长较长的效果更好;而离子型表面活性剂以亲水基团朝向CeO2粒子,亲水基团小的表面活性剂效果好,亲油基团的链长度影响不太明显。     

表面活性剂对相反转法制备金属颗粒的影响

采用相反转悬浮液体系中不同表面活性剂同步修饰的方法制备超细低熔点金属颗粒,研究阳离子和阴离子表面活性剂对金属颗粒的影响。通过沉降实验观察不同表面活性剂修饰的金属颗粒在水中的分散及稳定性,并采用激光粒度仪、扫描电镜对低熔点金属颗粒的粒径和形貌进行表征分析。结果表明:表面活性剂的种类对制备低熔点金属颗粒有重要的影响,其中阴离子表面活性剂的效果最好。对几种阴离子表面活性剂的研究表明:油酸钠的作用最明显,其浓度大小对低熔点金属颗粒的粒径、形貌和分散效果有显著的作用。采用质量分数为1%的油酸钠水溶液可制备出分散稳定、粒径分布窄和球状的超细低熔点金属颗粒,平均粒径为0.343μm。     

表面活性剂对纳米碱式碳酸镁的改性研究

采用不同种类的表面活性剂以及同一种类中不同的表面活性剂作为改性剂,利用沉降性试验和透射电镜对改性纳米碱式碳酸镁进行表征研究,结果发现,不同的表面活性剂对其改性效果不同,阳离子表面活性剂更有利于纳米碱式碳酸镁的分散及在水溶液中的稳定存在。     

不同分散剂中碳纳米管的定向操控技术

利用介电电泳可以实现悬浮液中碳纳米管的定向操控．碳纳米管可以用表面活性剂和有机溶剂进行分散．对比了表面活性剂（十二烷基苯磺酸钠,黏滞系数为1.312mPa·s）和有机溶剂（二甲基甲酰胺,黏滞系数为0．802mPa·s）,发现表面活性剂悬浮液中碳纳米管的溶解和分散效果好于有机溶剂中的溶解和分散效果,能实现单根分散．根据介电电泳原理,悬浮液中的碳纳米管在外加电场诱导下产生极化从而被驱动;分析了表面活性剂悬浮液和有机溶剂中碳纳米管的定向效果,发现有机溶剂中碳纳米管的定向效果好于表面活性剂悬浮液中的效果,表面活性剂悬浮液的黏滞系数大是阻碍外加电场有效定向操控碳纳米管的原因．     

表面活性剂对二氧化钛纳米流体分散性的影响

通过二步法将纳米二氧化钛分散到去离子水中,制备TiO2-水纳米流体。通过加入3种不同的表面活性剂作为分散剂,即阴离子表面活性剂十二烷基苯磺酸钠(SDBS)、非离子表面活性剂聚乙烯吡咯烷酮(PVP)和阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)制备出3种不同的纳米流体。用纳米粒度分析仪测定纳米流体中的纳米粒子的粒径和粒径分布,用Zeta电位分析仪测量纳米流体的电位,分析了不同浓度、不同种类的表面活性剂对水基TiO2纳米流体分散性的影响。     

聚合物分散剂对纳米TiO_2水悬浮液分散稳定性的影响

纳米TiO2复合乳胶漆的制备一般要求预先分散纳米TiO2并制成水悬浮液。为了制备稳定分散的纳米TiO2水悬浮液,研究了乳胶漆中常用的分散剂SN5040和PEG对纳米TiO2在水溶液中分散稳定性的影响,并分析了分散剂的作用机理。实验结果表明:SN5040能有效分散纳米TiO2,按照先SN5040后PEG的方式添加一定比例的混合分散剂,PEG能在SN5040吸附层上嵌入式吸附,显著提高了纳米TiO2的Zeta电位值,更有利于纳米TiO2水悬浮液的分散稳定性。红外光谱分析(FT-IR)表明:SN5040主要是通过与表面裸露的Ti4+形成配位键而吸附到纳米TiO2粒子表面上的。     

纳米流体的稳定性研究

从分散体系的稳定因素、纳米颗粒间的相互作用力、分散体系的沉降-扩散平衡、表面活性剂的作用等方面对纳米流体的稳定性进行了理论分析,结果表明,降低纳米颗粒的表面自由能、减小纳米颗粒与基液间的密度差、减小基液的黏度等都可提高纳米流体的稳定性。通过静置对比试验和TEM表征,研究了表面活性剂对提高纳米流体稳定性的作用。     

纳米流体的稳定性研究

从分散体系的稳定因素、纳米颗粒间的相互作用力、分散体系的沉降-扩散平衡、表面活性剂的作用等方面对纳米流体的稳定性进行了理论分析,结果表明,降低纳米颗粒的表面自由能、减小纳米颗粒与基液间的密度差、减小基液的黏度等都可提高纳米流体的稳定性。通过静置对比试验和TEM表征,研究了表面活性剂对提高纳米流体稳定性的作用。     

铬-纳米金刚石复合镀影响因素的研究

在对市售纳米金刚石进行适当的机械化学改性、分散及分级,制得粒度分布在150nm 以内、浓度可调、分散稳定、不含污染镀液成分的复合镀用纳米金刚石悬浮液的基础上,研究了工艺条件、纳米金刚石粒度和表面状态、镀液中添加表面活性剂对铬-纳米金刚石复合镀镀层性能的影响。结果表明,常规硬铬电镀工艺同样适合于铬-纳米金刚石复合镀;纳米金刚石团聚体解聚、粒度分布均匀和在镀液中稳定分散是得到高性能镀层的前提条件;颗粒能否在阴极粘附足够长的时间形成强吸附是颗粒沉积的关键,标准镀液中加入纳米金刚石镀层显微硬度反而降低,添加表面活性剂镀液中的复合镀层晶粒明显细化、显微硬度提高可达35%。     

纳米铜粉在无水乙醇中的分散稳定性

为了实现纳米颗粒的分级,研究影响纳米铜粉在无水乙醇中分散稳定性的因素。通过测定纳米铜粉分散在无水乙醇中形成的悬浮液的Zeta电位和吸光度,探讨悬浮液中分散剂的加入量和pH值对纳米Cu粉末在无水乙醇中的分散稳定性的影响。结果表明:当质量分数为0.01%的纳米铜粉分散在无水乙醇中,当分散剂加入量为0.008%(质量分数)时,分散稳定性最好。在此条件下,调节pH将降低其分散稳定性。     

Morphology and properties of ZnO nanostructures by electrochemical deposition: effect of the substrate treatment

Zinc Oxide (ZnO) nanostructures have been grown by electrochemical deposition on the indium-tin oxide (ITO) substrates. The influences and mechanism of pre-treatment of ITO on the morphology, density and size of ZnO nanostructures have been studied. Hexagonal dumbbell-like shape of ZnO bipods have been obtained because of the absence of nucleation sites on the unetched ITO substrate. An ITO etching process in dilute HCl results in the instantaneous and high density nucleation process, which was introduced to reduce the system energy and increase the growth density of ZnO nanostructures. Therefore, well-defined hexagonal and dense ZnO nanorods array are deposited on the etched ITO surface.     

真空蒸馏铟锡合金回收金属铟的研究

采用真空电阻炉对铟锡合金进行了实验研究。首先通过实验确定了较好的蒸馏时间和蒸馏温度范围。最后根据化验结果确定了对生产具有指导意义的实验条件,即对金属铟质量分数为90%的铟锡合金进行真空蒸馏时,采取的对生产具有指导意义的工艺条件为蒸馏温度1250℃,蒸馏时间60 min;蒸馏温度1300℃,蒸馏时间40 min;所得的金属铟的含铟量大于99%。     

Ultraporous poly(3,4-ethylenedioxythiophene) for nanometric electrochemical supercapacitor

Ultrathin films of poly(3,4-ethylenedioxythiophene) (PEDOT) have been prepared by electropolymerization on steel and indium-tin oxide (ITO) substrates under identical experimental conditions. Scanning electron microscopy and atomic force microscopy indicate that the substrate affects dramatically both the morphology and topography of films when the polymerization times are very short. An ultraporous three-dimensional network involving ultrathin sticks with a fiber-like morphology was formed on ITO. Asymmetric and symmetric supercapacitors have been fabricated by assembling electrodes of PEDOT deposited on ITO and steel. The specific capacitance, electrochemical stability, supercapacitor behavior and Coulombic efficiency measured for devices with an ITO/steel configuration were similar to those reported for advanced PEDOT-inorganic hybrid composites. Furthermore, the performance of the ITO/steel assembly is higher than those determined for symmetric supercapacitors derived from two identical electrodes of PEDOT deposited on steel or on ITO. The unique properties of the asymmetric supercapacitors have been attributed to the ultraporous structure of the ultrathin films deposited on ITO, which is not significantly perturbed when the device is submitted to a very high number of consecutive oxidation-reduction processes, and the different electroactivities of the two electrodes.     

Preparation and properties of RF sputtered indium-tin oxide thin films for applications as heat mirrors in photothermal solar energy conversion

In the present research, in order to deposit indium-tin oxide (ITO) thin films the method of RF reactive sputtering was used. Sputtering of two types indium-tin targets in the presence of oxygen as reactive gas was made. The technological parameters were optimized to obtain films with good quality on different substrates. The films' microstructure was studied by TEM and SAED. To identify the optical properties of the films the methods of infrared spectrometry and laser ellipsometry were used. UV-VIS spectrophotometry showed the high visible transmittance of the RF sputtered ITO films. Heating of the substrates during the films sputtering and their post deposition thermal treatment also were studied. The ultimate goal of the present research activities was to develop new technological processes leading to low-cost, highly effective optical coatings for application in photo thermal solar energy conversion and utilization.     

Improved performance of the single-layer and double-layer organic light emitting diodes by nickel oxide coated indium tin oxide anode

The electrical and optical properties of the NiO films deposited under various conditions were first characterized. An ultra-thin layer of nickel oxide (NiO) was then deposited on the indium-tin oxide (ITO) anode to enhance the hole injection in the organic light-emitting diode (OLED) devices. A very low turn-on voltage (3 V) was actually observed for the device with the ITO/NiO anode in the conventional double layer heterojunction OLEDs. The enhancement of hole injection by the ITO/NiO anode was further verified by the hole-only device and by the device with a patterned NiO layer on the ITO anode. The luminance and the current density of the single-layer OLED device were also significantly improved by using the ITO/NiO anode to enhance the hole injection. Although the luminescence efficiency was low, the reasons of low efficiency were studied and the improvement method was proposed. Our results suggest that the NiO/ITO anode is an excellent choice to enhance the hole injection in OLED devices.     

Modification of charge transport in triphenyldiamine films induced by acid oxidized single-walled carbon nanotube interlayers

We report the modification of the transport, optical and electrical properties of 200?nm thick N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'biphenyl-4,4'diamine (TPD) films on indium-tin oxide (ITO) when a low density of acid oxidized single-walled carbon nanotubes (o-SWCNTs) are present at the ITO/TPD interface. Most significantly, current-voltage measurements show strong evidence for a change from contact to bulk limited transport. We postulate that these observations result from a change in the structure of the TPD film seeded by the presence of o-SWCNTs at the ITO surface.     

Selective detection of a catecholamine against electroactive interferents using an interdigitated heteroarray electrode consisting of a metal oxide electrode and a metal band electrode

We developed an interdigitated array electrode (IDAE) consisting of a metal oxide electrode and a metal band heteroelectrode and employed it for the selective detection of catecholamines. We used an indium-tin oxide (ITO) film as the oxidation electrode of the IDAE because the ITO was able to suppress response currents from L-ascorbic acid (AA) and uric acid (UA), which are major electroactive interferents in biological fluids. However, the ITO film also suppresses the reduction of quinones including oxidized catecholamines. We developed a simple technique for fabricating our hetero IDAE, which also preserves the electrochemical properties of the ITO. When we compared hetero ITO-gold, homo ITO-ITO, and carbon-carbon IDAEs, we found that the hetero IDAE provided both high sensitivity and selectivity for DA detection. We achieved high selectivities for DA against AA and UA. The ratios of the response currents of AA and UA to DA were calculated as 6 and 5%, respectively.     

Oxygen plasma treatment effects of indium-tin oxide in organic light-emitting devices

The effects of oxygen plasma treatment on the surface properties of indium-tin oxide (ITO) substrates and its aging were investigated by X-ray photoelectron spectroscopy (XPS), contact angle, surface energy and polarity measurements. Experimental results demonstrate that the oxygen plasma treatment improves the stoichiometry of the surface and enhances the ITO wetting, so as to improve the surface properties of ITO substrates, due to the introduction of oxygen and the partial removal of hydrocarbon contaminants from the ITO surfaces. With the increment of aging time, however, the improved ITO surface properties are observed to tend to decay. Furthermore, the aging effect of treated ITO substrates on the performance of organic light-emitting devices (LEDs) was studied with respect to the driving voltage, brightness and efficiency. It is found that the device performance is subjected to the ITO surface properties and the ITO substrates aged for various times result in significant differences in electrical and optical characteristics which become worse as the aging time increases. The results indicate that the performance of organic LEDs is closely related to the surface properties of ITO substrates and the interface characteristics of ITO/organic layer.     

原子力显微镜与X射线光电子能谱对ITO表面改性的研究

采用氧气等离子体(OP)处理对氧化铟锡(ITO)薄膜进行表面改性,通过原子力显微镜(AFM)、X射线光电子能谱(XPS)和四探针等测试手段对薄膜样品进行表征,研究了OP处理对ITO表面性质的影响.实验结果表明OP处理有效去除了ITO表面的污染物,优化了ITO表面的化学组分,降低了ITO表面的粗糙度和方块电阻,改善了ITO的表面形态.与此同时,通过XPS监测研究了OP处理后ITO表面化学组分随老化时间的变化,结果显示经过优化的化学组分随老化时间增加而逐渐退化.另外,以OP处理后经过不同老化时间的ITO样品作为空穴注入电极,制备了有机电致发光器件(OELD),通过测试器件的电压-电流-亮度特性,进一步研究了ITO表面性质对于OELD光电性能的影响.     

Flexible organic light-emitting diodes with a polymeric nanocomposite anode

Flexible organic light-emitting diodes (FOLEDs) are facing mechanical issues arising from failure of the indium-tin oxide (ITO) films fabricated on flexible substrates. Polymeric nanocomposite anodes were fabricated by including single-wall carbon nanotubes (SWCNTs) in aqueous poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). The conductivity, transmittance and flexibility of the polymeric nanocomposite anode were characterized. The polymeric nanocomposite anodes fabricated on a poly(ethylene terephthalate) (PET) substrate exhibited superior bending properties to ITO anodes on PET. The FOLEDs fabricated on the polymeric nanocomposite anodes had a low turn-on voltage and higher luminous intensity than those fabricated on ITO/PET anodes. This flexible nanocomposite polymeric anode is a very promising for fully FOLEDs and other optoelectronics.