高分子/单链高分子纳米粒子复合体系中的界面性质

高分子与纳米粒子复合是改善高分子材料性能的有效途径.近20年来关于高分子/纳米粒子复合物的研究引起了学术界广泛的兴趣.然而由于此类体系中的影响因素复杂,虽然学者们在相关材料性能的研究方面取得了重要进展,但是相关理论的发展却相对滞后,其中一个重要原因是实验上表征手段的缺失,导致对体系中纳米粒子与本体高分子链相互作用规律的认识(尤其是两者界面性质的认识)不够.本文总结和阐述了我们近几年利用分子动力学模拟技术研究高分子/单链高分子纳米粒子复合体系的主要结果,并围绕此类复合体系中的界面结构及动力学性质,讨论并总结了纳米粒子对本体高分子链的作用范围及影响规律,指出单链纳米粒子对熔体链的作用范围与纳米粒子的自身尺寸相当,而与熔体高分子链的分子量没有直接的关系.该结论将为纳米复合体系高分子理论的发展提供重要参考.     

Influence of Poly (methyl metacrylate) Addition on Resistive Switching Performance of P3HT/P(VDF-TrFE) Blend Films

Organic semiconducting/ferroelectric blend films attracted much attention due to their elec-trical bistability and rectification properties and thereof the potential in resistive memory devices. Blend films were usually deposited from solution, during which phase separation oc-curred, resulting in discrete semiconducting phase whose electrical property was modulated by surrounding ferroelectric phase. However, phase separation resulted in rough surface and thus large leakage current. To further improve electrical properties of such blend films, poly(methyl metacrylate) (PMMA) was introduced as additive into P3HT/P(VDF-TrFE) semiconducting/ferroelectric blend films in this work. It indicated that small amount of PMMA addition could effectively enhance the electrical stability to both large electrical stress and electrical fatigue and further improve retention performance. Overmuch PMMA addition tended to result in the loss of resistive switching property. A model on the con-figuration of three components was also put forward to well understand our experimental observations.     

聚合物网络分散液晶复合膜的制备与性能研究

报道了一种新型树脂基的聚合物网络分散晶复合膜材料。研究了基体材料的组成，液晶种类，液晶含量，聚合温度，紫外光强度及聚合时间等聚合物网络分散液晶复合膜性能的影响。扫描电子显微镜观测，发现这种材料是由两个连相互穿构成了属于聚合物球型。     

聚合物掺杂的高亮度磷光有机电致发光器件

采用新型贵金属铱的配合物(pbi)2Ir(acac)作为客体磷光发光材料, 分别以4%和5%(w)的浓度掺杂于聚合物主体材料poly(N-vinylcarbazole) (PVK)中, 利用旋涂工艺制备了结构为indium-tin oxide (ITO)/PVK:(pbi)2Ir(acac)/2,9-二甲基-4,7-二苯基-1,10-菲咯啉(BCP)/Mg:Ag的有机电致发光器件, 对磷光材料(pbi)2Ir(acac)的紫外-可见吸收光谱﹑光致发光光谱以及聚合物掺杂的磷光器件的电致发光特性进行了研究. 结果表明, 两种掺杂浓度的器件均具有8 V左右的启亮电压, 器件在启亮后的最大流明效率分别为1.53和1.31 lm·W-1, 最大亮度分别为11210和9174 cd·m-2; 同时, 器件的电致发光光谱与色坐标均不随偏置电压和客体掺杂浓度的变化而改变, 具有稳定的色纯度. 分析了主体材料PVK到磷光客体(pbi)2Ir(acac)的能量转移机制, 并探讨了随着器件电流密度和客体掺杂浓度的逐渐增加, 器件流明效率的变化趋势.     

Organic Electrochemical Transistor Based on Hydrophobic Polymer Tuned by Ionic Gels

Hydrophobic conjugated polymers have poor ionic transport property, so hydrophilic side chains are often grafted for their application as organic electrochemical transistors (OECTs). However, this modification lowers their charge transport ability. Here, an ionic gel interfacial layer is applied to improve the ionic transport while retaining the charge transport ability of the polymers. By using the ionic gels comprising gel matrix and ionic liquids as the interfacial layers, the hydrophobic polymer achieves the OECT feature with high transconductance, low threshold voltage, high current on/off ratio, short switching time, and high operational stability. The working mechanism is also revealed. Moreover, the OECT performance can be tuned by varying the types and ratios of ionic gels. With the proposed ionic gel strategy, OECTs can be effectively realized with hydrophobic conjugated polymers.     

Interfacial Interaction of Polymer/Liquid Crystal Molecules and Electrooptical Properties of their Composite Systems

Polymer/liquid crystal composite films were prepared from a solution of polymer and nematic liquid crystal (LC) by a solvent casting method. The phase-separated structure of the composite film was controlled by the solvent evaporation rate. The light-scattering profile of a poly(diisopropyl fumarate)/LC: 40/60 w/w solution during solvent evaporation exhibited a periodic structure, indicating that the phase-separated structure was formed by spinodal decomposition. The aggregation structure of the composite film was investigated with a scanning electron microscope (SEM). SEM observation of the composite film suggested the presence of periodicity and dual connectivity of polymer and LC phases. The faster the solvent was evaporated, the smaller the LC channel (domain) size in the composite film. The composite film, composed of poly(methyl methacrylate) (PMMA) and a nematic LC (E44) with a positive dielectric anisotropy, exhibited remarkable and reversible light-scattering-light-transmission switching, under the modulation of an ac electric field. The light-scattering state was dependent on such optical heterogeneities as spatial distribution of the nematic directors and/or mismatching in the refractive indices of the components. The electrooptical behavior of the composite film was strongly dependent on the LC channel (domain) size in the composite film. The transmittance increased and the rise and decay response times (τ_R and τ_D), decreased and increased, respectively, with an increase in the size of the LC channel (domain).

The electrooptical switching properties for the polymer/LC composite film should be influenced by miscibility between the polymer and the LC phases. The miscibility between both phases was evaluated from a distribution of relaxation time for interfacial polarization. The anchoring effect was also investigated by measuring the nonlinearity of the dielectric constant for the composite system.     

Ag-PVA和Ag-PVA/TiO2复合超薄膜的制备及性能研究

用3种方法制备了银纳米粒子-聚乙烯醇复合体系,其中用加热还原法所得体系中Ag纳米粒子的尺寸较大(15nm),其表面等离子体共振吸收峰较宽,最大吸收波长位于420nm;用室温硼氢化钠还原法得到的复合体系的吸收峰蓝移至409nm,且峰形较窄,Ag纳米粒子的平均粒径为8.7nm;低温NaBH4还原法所得体系吸收峰进一步蓝移至397nm,此时Ag纳米粒子粒径最小(3.5nm).将室温还原法所得Ag-PVA复合体系旋涂成膜,所得薄膜光滑、透明、均匀性好,该法适用于制备多层薄膜,以调控薄膜的厚度和光谱性质.将Ag-PVA复合体系与钛酸四丁酯(Ti(O_nBu)₄)的乙醇溶液交替旋涂得到Ag-PVA/TiO₂有机/无机复合薄膜.紫外-可见吸收光谱研究表明,随着Ag-PVA层数的增加,薄膜的表面等离子体共振吸收强度呈线性增加,但是TiO₂层数的增加对吸收光谱没有明显影响.Ag-PVA/TiO₂有机/无机复合薄膜将金属纳米粒子、有机高分子与无机半导体材料结合在一起,这种多层纳米结构在光电、催化功能薄膜等方面具有潜在的应用前景.     

基于氧化铟锡电极的透明忆阻器件工作机制研究进展

随着电子技术的发展,兼具透明、柔性等特性的功能电子器件得到了广泛关注.作为新型电子存储器件,忆阻器在新一代信息技术领域(包括低功耗类脑计算、非易失逻辑、数据存储等)有着广阔的应用前景,成为近年来备受关注的新型纳米器件.氧化铟锡是一种常用的透明导电材料,因其优异的光学透明度、稳定的物理、化学特性等优点,成为制备新型透明忆...     

有机/无机异质结薄膜发光二极管

聚合物发光二极管（LED）自从Burrou吵es等于1990年首次报导PPV的电致发光［‘］以来，由于聚合物半导体具有热和化学性能的稳定，克眼了有机小分子材料容易晶化的优点，在平板显示领域必将占有一席之地，从而吸引了许多科学家投身到这一领域来．众所周知，要想实现LED的实用化     

8-羟基喹啉铝高分子薄膜的荧光特性

In this paper, the solid state. polymer thin films of 8-hydroxylquinoline aluminum (Alq3) were made by spinning coat method. The fluorescence efficiencies and the luminescence spectra of them were measured via the laser systems. Various experimental factors were considered and tested. It was found that the peak wavelength of the luminescence spectra of the Alq3 polymer films shifted and that the purity of the samples affected its fluorescence efficiencies: the fluorescence efficiencies of impure samples were about three-fourth of that of the purified ones; fluorescence efficiencies of Alq3 doped in PMMA polymer was higher than that doped in PC and PEO. Under certain conditions, transparent thin film 10 layers can be achieved. This kind of polymer thin film of Alq3 exhibits well fluorescence response, but also has good stability. Spin coat method can greatly reduce the technical requirements comparing with the vacuum plating method.     

有机/聚合物光导机理与图像传感器件

回顾了有机/聚合物图像传感器件的发展历程,从光导理论的高度评述了近20年来在有机/聚合物领域进行的科学探索和取得的重大进展,总结了改善光导性能、提高器件效率的主要手段,提出高性能光导材料的分子设计与原型光导传感器的若干原则,并对有机/聚合物图像传感器件的发展前景进行了综合分析.     

新型聚合物／液晶复合膜的研究：Ⅰ.膜材料对气体分离性能的影响

用顺丁橡胶，丁苯橡胶及聚氯乙烯与带有ＣＨ２＝ＣＨ－端基的液晶化合物共混，溶液浇铸法成膜，橡胶／液晶复合膜利用Ｓ２Ｃｌ２蒸气交联。用体积法测定膜的透气性，着重研究了不同基质材料及不同液晶类型对气体分离性能的影响。结果表明顺丁橡胶／液晶复合膜的透气系数最高，且分离性能也最好。     

带相反电荷高分子和表面活性剂复合物膜在空气/水界面上的特性

利用原子力显微镜技术、表面压松弛法对带相反电荷高分子和表面活性剂在气/水界面形成的界面复合物膜进行了特性研究.原子力显微镜研究结果表明,部分水解聚丙烯酰胺(HPAM)/十六烷基三甲基溴化铵(CTAB)所形成的界面复合物膜呈现出“团”状聚集体形貌.两性聚丙烯酰胺与CTAB形成的界面复合物膜呈现出“纤维丝”的聚集体形貌.亚相中盐的存在对界面复合物的形貌有很大影响.表面压松弛实验则进一步表明界面复合物膜形貌结构的变化对其膜稳定性有直接的影响.     

层层静电自组装构筑壳聚糖/磷钨酸复合膜的研究

将正电荷的壳聚糖与负电荷的磷钨酸溶液通过静电作用交替沉积在基底上组装复合多层膜。使用紫外可见光谱(UV-Vis)、红外光谱(FTIR)、X-射线光电子能谱(XPS)、原子力显微镜(AFM)和循环伏安法(CV)等手段对复合膜进行了表征。UV-Vis结果显示多层膜在特征吸收峰处的吸光度数值随膜双层数增加逐渐增大，呈良好的线性关系，表明多层膜是均匀组装的；XPS和FTIR结果证实了壳聚糖和磷钨酸被组装到膜上，AFM图形显示膜表面有一定的粗糙度，CV结果说明多层膜保留了磷钨酸的电化学性质。     

Organic/inorganic nanocomposite polymer electrolyte

The organic/inorganic nanocomposites polymer electrolytes were designed and synthesized. The organic/inorganic nanocom-posites membrane materials and their lithium salt complexes have been found thermally stable below 200℃. The conductivity of the organic/inorganic nanocomposites polymer electrolytes prepared at room temperature was at magnitude range of 10-6 S/cm.     

石墨烯/银复合薄膜的制备及表征

采用静电自组装技术,通过交替沉积聚(二烯丙基二甲基氯化铵)(PDDA)(或硝酸银)和氧化石墨烯,制备氧化石墨烯/PDDA薄膜和氧化石墨烯/硝酸银复合薄膜。然后在600℃下通入氩气和氢气进行气氛还原得到石墨烯薄膜和石墨烯/银复合薄膜。采用AFM、SEM、XPS、UV-Vis以及四探针电阻仪等对薄膜结构及性质进行表征。结果表明,通过静电自组装法可以获得生长均匀的薄膜。对比于相同自组装次数的石墨烯薄膜,石墨烯/银复合薄膜具有更好的透光性和更低的薄膜方块电阻。在λ=500 nm时,四层石墨烯/银复合薄膜的透过率为85%左右,而石墨烯薄膜的透过率为72%左右;石墨烯薄膜的方阻为161.39 kΩ.□-1,而石墨烯/银复合薄膜的方阻为99.11 kΩ.□-1。     

Inkjet-Printed TiO2/Fullerene Composite Films for Planar Perovskite Solar Cells

Perovskite solar cells have garnered and held international research interest, due to ever-climbing power conversion efficiency values, now >25 %. Some high efficiency configurations utilize a compact TiO₂ layer underneath a mesoporous TiO₂ layer, both of which require high temperature annealing steps that could hinder perovskite commercialization. To address the high thermal budget, we chose to use inkjet-printing to combine the two layers into a single TiO₂ film, which incorporates both nanoparticle and molecular precursor as well as organic fullerene additives. We printed the ink on fluorine-doped tin oxide, and after annealing at various temperatures, we found that 400 °C was the optimum annealing temperature for the inkjet-printed electron transport layers, which is significantly lower than the 500 °C required to anneal typical mesoporous TiO₂ films.     

“三明治式”多层Au/Pt复合薄膜的制备及其对甲醇的电氧化

采用界面组装、欠电位沉积和氧化还原置换反应组合方法制备了单层Pt/Au复合薄膜, 并且不需要任何有机偶联剂; 组装单层Pt/Au复合薄膜为三类多层Pt/Au复合薄膜: (Pt/Au)_n、Pt_m/Au和(Pt₃/Au)_k (n、m和k分别为Pt/Au、Pt和Pt₃/Au的层数). 采用电子显微镜研究了Au纳米粒子单层膜和Pt/Au复合多层膜的形貌. 对于所有的多层膜电极而言, 其电化学活性面积随着层数的增加而增加. 通过研究甲醇在每一类Pt/Au复合薄膜上的氧化电流密度, 考察了其对甲醇的电催化和抗毒化性能. 对于同一类复合薄膜而言, 甲醇分别在(Pt/Au)₃、Pt₃/Au和(Pt₃/Au)₂电极上均具有最大的氧化电流密度, 且优于本体Pt电极. 在这三种电极中, (Pt/Au)₃电极无论从电流密度上还是从抗毒化能力上讲, 其性能是最好的, 而且其抗毒化能力也优于商业Pt/C催化剂. 这种良好的催化性能源于Au和Pt之间最大化的协同效应, 这取决于Pt和Au原子比率以及Pt纳米层和Au纳米层之间的排布方式.     

新型Ti3C2 MXene的化学制备及基于MXene忆阻器特性与机理

阻变器件是一种微电子器件,具有阻值可在两个甚至两个以上的阻态之间重复变化的特点。忆阻器作为新型的阻变器件,具有可连续变化的丰富阻态。近年来因其具备简单的二端结构、高集成度以及低工作电压等特性,在新型非易失性存储以及构建神经形态系统等方面被广泛研究。但其在实现应用的过程中仍存在着稳定性较差等问题。近期一些工作证明了二维材料如氧化石墨烯在优化忆阻器性能方面具备良好的应用潜力。MXene是一种具备类似石墨烯结构的新型二维过渡金属碳/氮化物,因其具备二维层状结构显现出特殊的力学以及电学特性,有望应用于忆阻器中以提高器件的电学性能。在本文中,我们通过化学湿法刻蚀制备了Ti₃C₂粉末,通过旋涂工艺在忆阻器结构中引入Ti₃C₂薄膜。Ti₃C₂ MXene与SiO₂同时作为忆阻器阻变层,制备了Cu/Ti₃C₂/SiO₂/W结构的忆阻器,并且对其相关电学特性进行了探究。在该器件上,通过实验测得忆阻器典型的开关特性曲线并在双向直流电压下针对高、低阻态的可重复性、稳定性进行了实验。结果表明该器件能够在100个扫描循环过程中保持稳定的高、低阻态达到10⁴ s以上。同时,该器件状态能够受脉冲电压调节,实现突触间典型的双脉冲易化行为。实验结果表明基于Ti₃C₂ MXene的忆阻器将有望应用于构建新兴存储设备以及人工神经形态系统。     

La and Sr Composite Oxides-modified Graphite Felt for Aqueous Organic Redox Flow Batteries

In this study, aqueous organic redox flow batteries(AORFBs) with NaCl as supporting electrolyte were investigated. In AORFBs, the chlorine evolution reaction should be retarded, not the hydrogen evolution reaction. To enhance the catalytic activity of the graphite felt(GF) electrode, the metal oxides were proposed to decorate on the GF surface. Among the loading oxides, significant enhancement of the mass transfer and reaction activity was obtained by the presence of LaSrO_x nanoparticles. X-Ray photoelectron spectroscopy and contact angle measurements revealed that the content of oxygen-containing groups and the hydrophilicity were remarkably increased. After the electrode assembled in the battery, the LaSrO_x/GF electrode presented huge enhancement of the battery performance, obviously increasing in the battery capacity and efficiency. At a current of 50 Am/cm², the energy efficiency(EE) of the battery increased from 54.76% to 61.37% by the LaSrO_x/GF electrode. Furthermore, the cyclability of the system tested that no obviously fading was observed after 100 cycles, signifying the excellent stability of the LaSrO_x/GF electrode.