高稳定性的偶氮聚合物薄膜光致取向与弛豫的研究

合成了一种新型的偶氮聚合物,它是由吡啶基团和4-腈基-4′-羟基偶氮苯聚合而成.搭建了偶氮聚合物薄膜光致双折射探测光路系统,并测量了吡啶基团和4-腈基-4′-羟基偶氮苯的摩尔比分别为O,0.25,0.5,0.75,1的偶氮聚合物薄膜的光致取向和弛豫曲线,并做了反复写入和擦除实验以及老化实验.实验结果表明:这种偶氮吡啶聚合物光致取向十分稳定,两种单体的摩尔比越高,偶氮聚合物双折射值越大.值得关注的是摩尔比低于50％时,偶氮聚合物薄膜弛豫表现为曲线缓慢下降最后趋向平衡.而当摩尔比高于50％时,偶氮聚合物关闭泵浦光后曲线缓慢上升最后趋向平衡,这个实验结果说明了摩尔比超过50％的偶氮聚合物其保存写入信息的能力增强了,因而也更稳定了.     

特性炔类液晶的简便合成

4,4′-二烷基-4-乙炔基联环己烷(1)和它的偶联衍生物1,4-双((4,4′-二烷基-联环己)-4-基)丁二炔(2)、1,4-双(2-((4,4′-二烷基-联环己)-4-基)乙炔基)芳烃(3)是具有某种特性的重要液晶化合物。文章介绍了以4,4′-二烷基联环己基-4-甲腈(4)为起始原料的化合物的合成。首先,化合物(4)与甲基锂发生加成反应,水解后制得关键中间体甲基酮化合物(5),接着甲基酮化合物(5)与格氏试剂在特定的条件下反应,高收率地制得炔类化合物(1),关于本反应可能的机理文中也进行了阐述。化合物(1)通过氧化自偶联制得化合物(2)。化合物(1)与二卤代芳烃在Pd(0)催化系统下发生偶联制得化合物3,这些化合物的制备具有短的合成步骤和高的反应收率,是高效的合成方法;其中化合物(1)的制备方法从未见诸于以前的任何文献报道。     

蚀刻腔条件对刻蚀工艺的影响研究

在ULSI制造中蚀刻腔条件的变化是导致刻蚀工艺重复性差的一个重要原因.在刻蚀过程中,一层聚合物会淀积在蚀刻腔壁上.通过XPS分析得知,聚合物的主要成分为(CF2)n.实验过程发现不同的聚合物量会影响等离子体中CF2基团的浓度.聚合物越多,CF2浓度越高;反之,聚合物越少,CF2 浓度就越低.在这种情况下,蚀刻腔上的聚合物被认为是等离子中CF2基团的一个源.CF2浓度的变化又导致最终刻蚀特性(CD,蚀刻率)的变化和工艺漂移.     

宽发射聚芴衍生物的合成及其光谱特性

利用Stille偶联聚合反应,将二溴苯并噻二唑、2,5-二噻吩双三丁基锡、9,9-二辛基2,7-二溴芴进行聚合,得到了一种在可见光区具有宽发射范围的三元共聚物,该聚合物的发射光谱涵盖了整个可见光区,发光峰位于470.7,498.9,654.2nm,具有成为单层聚合物白光材料的潜力。     

蓝光共轭聚合物:聚(2,5-二己氧基)苯的合成及表征

以三氯甲烷为溶剂，采用三氯化铁氧化偶联反应合成了一种可溶性对称烷氧基取代聚对苯衍生物：聚（2，5-二己氧基）苯（DHO-PPP）。该聚合物可以很容易地通过溶液方式成膜，聚合物的结构通过红外光谱、核磁共振氢谱得到了确认，发现其中含有45％的聚（2，5-二己氧基-1，3）苯成分。在紫外-可见吸收光谱上，聚合物的三氯甲烷溶液的最大吸收峰位于351nm，与无取代的聚对苯相比红移了50nm。在300nm激发光下，聚合物的氯仿溶液发出了423．8nm的蓝光，表明材料是一种良好的蓝光材料。热重分析表明聚合物具有非常优异的热稳定性，在300℃时的质量损失只有2％。差示扫描量热法分析表明聚合物的玻璃化转变温度为102．34℃。X射线衍射分析表明，DHO-PPP是一种具有部分微晶结构的材料。     

高折射率聚合物/纳米粒子激光雕刻材料的制备

为了提高双光子聚合立体光雕微结构的应用性,需要提高雕刻材料的折射率。TiO2粒子具有很高的折射率,通过向光敏聚合物中加入TiO2粒子,制成了聚合物/纳米粒子复合材料,有效地提高了雕刻材料的折射率。聚合物/纳米粒子复合材料的透过率和吸收率图显示,这种材料适合进行双光子聚合雕刻。     

基于FPGA的级联结构FFT处理器的优化设计

为了减少级联结构FFT处理器对缓冲存储器需求量,提出一种基于FPGA用基-16和基-2、基-4、基-8组合的混合基算法实现FFT处理器的设计方案。在1 024点FFT处理器的实现过程中,用优化的基-4蝶形运算核搭建了级联结构的基-16蝶形运算核,并将对同一个地址进行读和写的双端口RAM和乒乓结构的单端口RAM结合使用,从而在不增加逻辑单元使用和保证运算速度的情况下,大大减少了存储单元的使用量。     

二乙胺聚合膜特性研究

用等离子体方法将二乙胺单体聚合成聚二乙胺薄膜。红外光谱分析表明聚合膜中有 C- H,C- N及 N- H键存在。实验表明聚合膜性能同聚合工艺条件特别是射频放电电压有关。放电电压增加 ,热稳定性增加。聚合膜中碳含量增加而氢含量减少。在放电电压较低条件下聚合物具有长程无序态结构。而放电电压增大 ,等离子体中受激碳原子从电场中获得较多能量 ,在交联过程中能够调整其在网络结构中的位置 ,因而无序程序降低 ,有序态增加 ,甚至出现晶化现象。     

聚合条件对PEDT导电性及相对分子质量的影响

采用化学原位氧化聚合法制备了导电聚合物3,4-聚乙烯二氧噻吩(PEDT)薄膜。系统研究了不同工艺条件对聚合物电导率的影响。发现单体与氧化剂体积比为1∶4、溶剂含量90%(体积分数)、加入聚合改良剂0.5%(体积分数)、反应温度–5℃时可以获得较高电导率(>20S/cm)薄膜。首次结合元素分析法,研究了工艺条件对聚合物相对分子质量的影响,结果表明,聚合温度25℃,ψ(单体:氧化剂:聚合改良剂)=1∶4∶2的条件下,所合成的PEDT可获得最大平均相对分子质量(1068)和聚合度(7.6),并对相应的机理进行了探讨。     

沉淀聚合法制备电泳显示白色球形复合粒子的机理(英文)

基于二氧化钛的特性和4-乙烯基吡啶的功能,利用沉淀聚合法在甲醇中合成出二乙烯基苯-苯乙烯-4-乙烯基吡啶共聚物包覆的二氧化钛多核的表面光滑的球形粒子。利用DSC和TG检测了聚合效果,通过傅里叶红外光谱证实了聚合物的结构单元,利用SEM观察了复合粒子的表面,获得了具有稳定性、表面光滑的球形微粒。相应的聚合机理通过分析一系列制备核壳微球方法所得产物的SEM照片和改变一些参数所得的结果得以证实。分散的顺序和4-乙烯基吡啶的用量决定了生成复合球形微粒的机理。进而,通过溴代烷烃和在甲醇中沉淀聚合产物表面的4-乙烯基吡啶化合而成的季铵盐证实了复合微粒的电泳特性。     

Electrooptic light modulation and second-harmonic generation in novel diazo-dye-substituted poled polymers

The nonlinear-optical susceptibilities, x/sup (2)/, of a diazo-dye-substituted polymer poled with high electric fields were determined experimentally and theoretically. The electrooptic modulation of He-Ne laser light in a traveling-wave channel-waveguide modulator using the diazo-dye-substituted poled polymer is reported, and the linear electrooptic coefficient of the poled polymer is estimated from a measured half-wave voltage. The polymer studied is a poly(methyl methacrylate) copolymerized with a methacrylate ester of the dicyanovinyl-terminated diazo dye derivative. This polymer is called 3RDCVXY. The corona-poled 3RDCVXY polymer exhibits a x/sup (2)/ value of 1*10/sup -6/ esu at 1.06 mu m. The thermal stability is excellent even at 80 degrees C. The poled 3RDCVXY polymer film shows a linear electrooptic coefficient as high as 40 pm/V at 0.633 mu m. An electrooptical light modulation in the channel 3RDCVXY polymer waveguides with a half-wave voltage as low as 5 V was obtained.<>     

Both p- and n-type dopable polymer toward electrochromic applications

Synthesis and electrochemical polymerization of 8,11-bis(4-hexylthiophen-2-yl)acenaphtho[1,2-b]quinoxaline (HTAQ) were performed. The polymer was characterized by cyclic voltammetry, UV–Vis-NIR spectroscopy and colorimetry. Cyclic voltammetry studies revealed that the polymer was susceptible to both p- and n-doping. The electroactive polymer has fast switching time and high optical contrast. Spectroelectrochemistry also showed that the polymer is capable of being switched from bluish-green and a highly transmissive green upon p-type doping. Highly fused nitrogen containing acceptor group was utilized in the polymer backbone which was resulted in a polymer that has a significant potential for n-type doping. The existence of a true n-type doping process was proven by the results of both cyclic voltammetry and spectroelectrochemistry studies.     

Characterization of adhesion property between fused silica and thermoplastic polymer film in thermal nanoimprint lithography using a novel pull-off test

A novel pull-off test that mimics the actual thermal NIL process was conducted to investigate the adhesion properties between a flat fused silica and thermoplastic polymer film used in thermal NIL process. The pull-off force was measured under various NIL conditions—such as use of various polymer materials, imprint pressures, and separation velocities—and the surfaces of the mold and polymer film were observed after the test. The anti-sticking layer (ASL) derived from (1H,1H,2H,2H-perfluorooctyl)trichlorosilane (F₁₃-OTS) was coated on the fused silica and its effects on the adhesion characteristics was also examined. In cases of the mold without ASL, the pull-off force varied significantly according to the process conditions and damage on the polymer film was observed in most of the tests. In cases of the mold coated with the ASL, on the other hands, the pull-off force was maintained at a lower level in the range of the imprint pressure from 2 to 10 MPa or separation velocity from 1 to 25 μm/s, and there was no damage to the polymer film due to adhesion.     

仿壁虎微纳米粘附阵列的工艺制作

介绍了采用微纳米加工技术制作仿壁虎脚趾粘附阵列的工艺方法。用ICP设备制作具有微米孔阵列的硅模板,用聚合物浇注,脱模后得到直径分别为2μm和5μm的微米阵列;浇注具有纳米孔径的氧化铝模板,脱模后得到直径约100nm的柔性纳米阵列。     

PMMA基凝胶聚合物电解质MnO2电容器的研究

以沉淀法制备的MnO2为正极材料,活性炭(AC)为负极材料,甲基丙烯酸甲酯(MMA)作聚合物单体,碳酸二甲酯(DMC)与碳酸乙烯酯(EC)的混合液作增塑剂,高氯酸锂为支持电解质,采用内聚合法制备PMMA基凝胶聚合物电解质MnO2/AC混合电容器。测试结果表明,随着MMA含量的降低,凝胶聚合物电解质的电导率增大,电容器的比容量也随之增大,当MMA的含量为20%时,凝胶聚合物电解质的电导率可达6.1×10–3S/cm,比容量为34.02F/g。     

Distributed feedback polymer laser with an external feedback structure fabricated by holographic polymerization technique

Distributed feedback polymer laser with a grating in the waveguide cladding layer was prepared by holographic polymer dispersed liquid crystals (HPDLCs). The holographic polymerization technique enables one-step formation of an organic grating on top of a homogenous semiconducting polymer poly(2-methoxy-5-(2′-ethyl-hexyloxy)-p-phenylenevinylene) (MEH-PPV) layer. Under optical pumping, a lasing threshold of 21 μJ/cm² and a bandwidth of 0.7 nm were obtained in a single longitudinal mode operation. Further studies on the effect of the semiconducting polymer thickness show the amount of evanescent wave spread into the grating layer determines the laser performance of the proposed device.     

Stable Blue Emission from a Polyfluorene/Layered‐Compound Guest/Host Nanocomposite

In this study a blue‐light‐emitting conjugated polymer, poly(9,9‐dioctylfluorene), is confined to the interlayer space of inorganic, layered metal dichalcogenide materials, metallic MoS₂, and semiconducting SnS₂. The nanocomposites are prepared through Li intercalation into the inorganic compound, exfoliation, and restacking in the presence of the polymer. X‐ray diffraction and optical absorption measurements indicate that a single conjugated polymer monolayer, with an overall extended planar morphology conformation, is isolated between the inorganic sheets, so that polymer aggregation or π–π interchain interactions are significantly reduced. Photoluminescence (PL) measurements show that the appearance of the undesirable green emission observed in pristine polymer films is suppressed by incorporating the polymer into the inorganic matrix. The blue emission of the intercalated polymer is stable for extended periods of time, over two years, under ambient conditions. Furthermore, the green emission is absent in the PL spectra of nanocomposite films heated at 100 °C for 7 h in air with direct excitation of the keto defect. Finally, no green emission was observed in the electroluminescence spectrum of light‐emitting devices fabricated with a polymer‐intercalated SnS₂ nanocomposite film. These results support the proposed hypothesis that fluorenone defects alone are insufficient to generate the green emission and that interchain interactions are also required.     

光学高分子薄膜纳米结构与性能关系的探讨

应用AFM及力曲线的统计方法(forcecurvemethod)和Tapping/Phase功能,比较系统地研究了Glass/ITO基底上旋涂厚度为5μm的非线性光学功能高分子薄膜。结果发现,不同基底对于薄膜结构及分子构象没有明显影响。客体分子(molecule-2)在常温条件下能够以氢键的方式镶嵌在主体高分子(molecule-1)链上的—OH官能团周围和相邻的分子链间,形成特征的纳米级带状结构。ITO基底上非线性光学功能高分子薄膜在160～180℃条件下和经3000V强电场极化后,客体分子和主体高分子不同程度地进行了化学交联反应,生成新的非线性光学高分子;薄膜的微观结构由常温时的带状结构变为纳米环状结构,膜表面呈现出均匀平滑的表面形貌,并获得了理想的电光性能信号。分子键合类型的变化使得薄膜的组分发生了变化,并引起了薄膜的微观结构的改变。力曲线的统计方法和Phase的相关信息为此提供了重要证据。     

Processable and multichromic polymer of bis-3-hexylthiophene substituted 4-tert-butylphenyl quinoxaline

A new polythiophene derivative, poly-2,3-bis(4-tert-butylphenyl)-5,8-bis(4-hexylthiophen-2-yl)quinoxaline (PHTQ) was synthesized by both chemical and electrochemical polymerization and its electrochemical properties were reported. The monomer was electrochemically polymerized in the presence of tetrabutylammonium hexafluorophosphate (TBAPF₆) as the supporting electrolyte in dichloromethane–acetonitrile (5:95, v:v). Nuclear magnetic resonance (¹H NMR) and Fourier transform infrared (FTIR) were utilized for the characterization of the monomer and the soluble polymer. The polymer was further characterized by gel permeation chromatography (GPC). Spectroelectrochemistry and switching ability of the polymer were investigated by UV–vis spectrophotometer and cyclic voltammetry. The polymer revealed three distinctive colors upon doping which indicated that the polymer is multichromic. tert-Butyl group on the pendant phenyl rings and hexyl groups on thiophene eased the solution processability of the electrochromic polymer. The electrochemical and spectral properties of the chemically synthesized polymer were investigated via spray coating on ITO glass slides.     

串联2—2复合材料的介电击穿研究

研究了串联2－2型复合材料的介电击穿特性。串联2－2型压电复合材料结构较为简单，它是研究具有复杂连通性压电复合材料的基础。根据能量守恒定律，推导出串联2－2复合材料中压电陶瓷PZT层上和聚合物PVDF层上的电场强度Ec、Ep。由于压电陶瓷的介电常数εc(≈1600ε0)远远大于聚合物的介电常数εp(≈12εo)，因此Ep远远大于Ec。尽管PVDF的介电强度高于PZT的介电强度，但由于Ep远远大于Ec，所以串联2－2型压电复合材料的介电击穿往往是从聚合物层开始的，最后导致复合材料整体被击穿。对理论计算进行了实验验证，结果表明：在PZT含量较低时，计算值与试验值比较接近，但随着复合材料中PZT含量的提高，二者的偏差越来越大。文章最后定性讨论了在高PZT含量时复合材料的计算值与试验值偏差较大的原因。