有机金属聚合物/多酸纳米杂化LB膜的制备与光电性质研究

以含有共轭大π键的有机金属聚合物(OMP)作有机组分, 以Keggin结构和Dawson结构钨(钼)磷杂多酸作无机组分, 以十八胺为辅助成膜剂, 用LB技术制备了3种新型有机金属聚合物/十八铵/杂多阴离子OMP/ODA/HPA (HPA＝PMo₁₂, PW₁₂, P₂Mo₁₈)杂化LB膜. 用π-A曲线﹑UV-vis吸收光谱﹑荧光光谱﹑原子力显微镜(AFM)﹑扫描隧道显微镜(STM)和表面光电压谱(SPS)对标题LB膜的成膜性能及光电性质进行了研究, 结果表明标题杂化LB膜的崩溃压为26.8 mN/m, 在可见光区有较强的光电压响应, 并有好的发光性质. 当电压为±8.0 V时, 隧道电流是－0.1～－2.3 nA.     

对叔丁基杯[8]芳烃/钼磷杂多酸纳米杂化LB膜的制备与表征

以含有共轭大π键的对叔丁基杯[8]芳烃(Cal8)和十八(烷)铵(ODA)与Keggin结构和Dawson结构钼磷杂多酸(HPA)做成膜材料, 用LB技术制备了2种新型无机-有机杂化LB膜. 用π-A曲线、UV-Vis吸收光谱、荧光光谱和原子力显微镜(AFM)对标题LB膜的成膜性质、结构及发光性质进行了表征. 结果表明在空气/水界面Cal8/ODA/HPA杂化可形成稳定的单层与多层膜. 标题杂化LB膜的崩溃压为39.0 mN/m, 其粒子具有纳米尺寸, 在激发波长为280 nm时, 可观察到322～387 nm处由Cal8分子π-π*跃迁引起的荧光发射峰及510 nm处 杂多阴离子的配体到金属的荷移跃迁(LMCT)三重发射谱带.     

多金属氧簇与倍半硅氧烷簇构筑的哑铃形杂化分子Langmuir膜和Langmuir-Blodgett膜

以两个形状杂化分子(Shape Hybrid Molecules)为目标分子, 研究了它们在气液界面上形成Langmuir膜的过程和Langmuir-Blodgett (LB)膜的聚集态结构. 杂化分子是由Wells-Dawson型磷钨氧簇(Polyoxometalates, POMs)和T₈型的倍半硅氧烷簇(Polyhedral Oligosilsesquioxane, POSS), 通过对苯二甲酸有机连接链(OL)用共价键构筑的具有杂化性质和哑铃形状的簇-簇杂化分子(POM-OL-POSS). 这两种杂化分子的差别在于POSS段中, 外围有机基团的尺寸不同. 在实验中, 采用Langmuir和LB膜技术, 了解POSS外围的七个取代基变化导致的分子尺寸变化对Langmuir膜形成过程和LB膜结构的影响. 采用Langmuir技术测定了表面压-平均分子面积(π-A)等温曲线和π-A循环等温曲线, 跟踪并研究了这两个杂化分子在水表面上形成Langmuir膜的过程. 实验结果表明, 两个杂化分子都表现出良好的两亲性, 从气相变化到固相的过程中, 杂化分子经历了从分散到集中的过程. 将这些膜转移到基片上, 得到单层的LB膜, 再利用原子力显微镜(AFM)和透射电子显微镜(TEM)研究了LB膜的表面形貌和聚集态结构. 由于POM段中含有钨和钒金属, 可以直接用TEM观察聚集态结构, 发现了在气-液和液-固相转变过程中, LB膜中杂化分子的聚集态结构都呈现涨落特征, 一种凝聚态物理中由相转变导致结构涨落的重要物理现象. 本研究获得的结果能够帮助我们以及这个领域的研究者们继续优化杂化分子的结构, 进一步构筑具有有序结构的膜和本体材料.     

8-羟基喹啉两亲配合物的LB膜及其电致发光器件研究

制备了两亲配体N-十六烷基-8-羟基-2-喹啉甲酰胺(HL)十个配合物的LB膜。采用π-A等温线和小角X射线衍射等方法研究了这些LB膜的性质和结构。两亲配合物的单分子占有面积为(1.25±0.06)nm^2和(0.75±0.06)nm^2,分别对应于两亲分子中两个喹啉环平躺和环与环之间以一定的角度倾斜于气/水界面。LB膜内分子排列是二维有序的超晶格结构,双层高度(5.0±0.1)nm;LB膜具有导电各向异性,其平面和垂直直流电导率分别为10^-^5S.m^-^1和10^-^9S.m^-^1;LB膜的高荧光性质使之可以用作为电致发光器件的发光材料。以LaL~2(H~2O)~4Cl的LB膜为发光层的单层电致发光器件的驱动电压为9V,发光亮度330cd/m^2,为黄绿色发光。     

聚喹啉/十八胺/稀土杂多阴离子杂化LB膜的制备、结构及电性质

将聚喹啉(PQ)、十八胺(OA)和含稀土元素的1;11钨系双系列杂多阴离子RE(PW₁₁O₃₉)₂^11-(RE=Ce^Ⅲ,Eu^Ⅲ,Gd^Ⅲ)通过LB技术掺杂,成功地制备了三种PQ/OA/稀土杂多阴离子杂化LB膜,通过π-A曲线、荧光、吸收光谱和原子力显微镜等手段对PQ/OA/稀土杂多阴离子杂化LB膜的成膜方式、性能、结构及形貌进行了表征;扫描隧道显微镜研究表明,将稀土杂多化合物掺杂到聚喹啉中可使聚喹啉的导电性明显增强.     

聚乙烯咔唑/杂多阴离子杂化LB膜的制备、结构与光电性质

首次选用聚乙烯咔唑（PVK）、二十二烷酸（BA）与杂多阴离子用LB技术制备 了五种有机/无机杂化LB膜，PVK/BA/HPC（HPC = Na_5(PZ(H_2O)Mo_(11)O_(39)]· 5H_2O, Z = Mn, Co, Cu, Zn, Ni）。用原子力显微镜（AFM），UV-vis，小角X射 线衍射（LAXRD），表面光电压谱（SPS），荧光光谱等对LB膜的结构与性质进行了 表征。结果表明：它们在空气/水界面有好的成膜性能，崩溃压为22 ～27 mN/m， 杂多阴离子作为一个单层夹在PVK和BA双层之间。PVK/BA/HPC LB膜的光致发光具有 PVK激基缔合物的特征荧光，其光电压谱有较强的光电响应。     

两亲性卟啉-紫精化合物LB膜的结构及光电性质研究

本文制备了两亲性卟啉-紫精化合物的LB膜材料, 用π-A等温曲线、吸收光谱、小角和低角X射线衍射以及扫描隧道电镜(STM)等方法研究了LB膜的结构。结果表明, LB膜内分子排列是二维有序的超晶格结构, 卟啉环在基片上的排列呈"站立"状态。单个分子占有面积为1.15nm^2, 单层高度为2.35nm, 相邻裂间的距离为1.07nm。这种规则有序的两亲性卟啉-紫精化合物呈现出良好的光量子收率和光电响应特性。     

甲基丙烯酸—磷脂酰乙醇甲基丙烯酰胺共聚物LB膜的研究

制备了不同摩尔比的甲基丙烯酸-磷脂酰乙醇甲基丙烯酰胺共聚物,研究了这种共聚物在水面的表面压力(π)-分子面积(A)曲线、共聚物制成的MOS LB膜的电容(C)-电压(V)特性及此LB膜的相变温度。     

基于改性亚麻仁油的有机/无机光固化膜的光固化机理及其反应性研究

用亚麻仁油和环戊二烯合成了改性亚麻仁油(NLO)光固化低聚物,其结构用红外光谱(FT-IR)进行了表征.基于改性亚麻仁油、巯基硅氧烷和光引发剂制备了有机/无机杂化光固化膜,对其光固化机理进行了分析,对无机粒子在改性亚麻仁油中的分布用AFM(原子力显微镜)进行了观测,建立了该有机/无机杂化体系的光固化模型.对杂化膜光固化反应性用Photo-差示扫描热分析仪(Photo-Differential Scanning Calorimeter)进行了测试,Photo-DSC测试结果表明:巯基硅氧烷能大大提高改性亚麻仁油体系光固化速率,环烯键对硫醇十分敏感.     

聚酰亚胺LB膜真空热解制备β-SiC膜的STM观察

扫描隧道显微镜 ( STM)是一种基于量子隧道效应对样品进行高分辨无损测试的表面测试技术 [1] ,它可以在原子水平上反映表面分子或原子的排列分布情况 ,在物理、化学、生物和微电子界受到高度的重视 .STM技术以及其后发展起来的原子力显微镜 ( AFM)特别适合 LB膜的研究 ,能直观地反映出 LB膜中分子排列的微观结构以及表面缺陷 [2 ,3] .我们曾通过真空热解沉积在单晶硅片上的聚酰亚胺L B膜制得了准单晶β- Si C超薄膜 [4～ 6 ] .本文利用 STM技术对聚酰亚胺 LB膜以及由它真空热解而成的 Si C膜的表面形态结构进行了初步观察和分析 .…     

Preparation,characterization, and electrical properties of dual‐emissive Langmuir‐Blodgett films of some europium‐substituted polyoxometalates and a platinum polyyne polymer

A new series of organometallic/inorganic composite Langmuir‐Blodgett (LB) films consisting of a rigid‐rod polyplatinyne polymer coordinated with 2,7‐bis(buta‐1,3‐diynyl)‐9,9‐dihexylfluorene (denoted as PtP) as the π‐conjugated organometallic molecule, an europium‐substituted polyoxometalate (POM; POM = Na₉EuW₁₀O₃₆, K₁₃[Eu(SiW₁₁O₃₉)₂] and K₅[Eu(SiW₁₁O₃₉)(H₂O)₂]) as the inorganic component, and an amphiphilic behenic acid (BA) as the auxiliary film‐forming agent were prepared. Structural and photophysical characterization of these LB films were achieved by π–A isotherms, absorption and photoluminescence spectra, atomic force microscopy imaging, scanning tunneling microscopy, and low‐angle X‐ray diffraction. Our experimental results indicate that stable, well‐defined, and well‐organized Langmuir and LB films are formed in pure water and POM subphases, and the presence of Eu‐based POM in the subphase causes an area expansion. It is proposed that a lamellar layered structure exists for the PtP/BA/POM LB film in which the POM and PtP molecules can lay down with the interfacial planes. Luminescence spectra of the prepared hybrid LB films show that near‐white emission spectra can be obtained due to the dual‐emissive nature of the mixed PtP/POM blends. These Pt‐polyyne‐based LB films displayed interesting electric conductivity behavior. Among them, PtP/BA/POM 13‐layer films showed a good electrical response, with the tunneling current up to ±100 nA when the voltage was monitored between ?1 and 7 V. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 879–888, 2010     

Polyplatinayne/polyoxometalate composite Langmuir‐Blodgett films: Preparation,structural characterization,and potential optoelectronic applications

A new family of organometallic/inorganic composite Langmuir‐Blodgett (LB) films consisting of rigid‐rod polyplatinayne polymer ([Pt‐T(OMe‐Fl)T]_∞ or [Pt‐T(F‐Fl)T]_∞, where the triplet bonds are abbreviated by T, and fluorene ring by Fl) as the π‐conjugated organometallic molecule, polyoxometalate (POM, POM = K₃PMo₁₂O₄₀, H₃PW₁₂O₄₀, or H₆P₂W₁₈O₆₂) of the Keggin and Dawson structures as the inorganic component, and dimethyldioctadecylammonium bromide (DODA) or a mixture of octadecanoic acid (OA) and docosanoic acid (DA) as the auxiliary film‐forming agent were prepared and characterized by π–A isotherms, UV–Vis absorption spectra, photoluminescence spectra, atomic force microscopy imaging, scanning tunneling microscopy, and low‐angle X‐ray diffraction. Our experimental results indicate that steady, even, and ordered Langmuir and LB films are formed in pure water and polyoxometalate subphases. It was shown that the POM molecules are probably embedded inside the polyplatinayne molecules in the LB film structure and they can quench the luminescence of the Pt polyyne. These Pt‐polyyne based LB films display interesting electric conductivity behavior. [Pt‐T(OMe‐Fl)T]_∞/DODA/HPW₁₂ monolayer film shows a good electrical conductivity, and the tunneling current amounts to ±100 nA when the voltage is set at ±8 V. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3193–3206, 2008     

Preparation, luminescence and photoelectric properties of Langmuir-Blodgett films of alkynylplatinum(II)-zinc(II) porphyrinate/heteropolyoxometalate hybrid composites

A new class of organometallic/inorganic hybrid Langmuir-Blodgett (LB) films, consisting of rigid-rod alkynylplatinum(II)-zinc(II) porphyrinate complex (OMA) as the π-conjugated donor-acceptor-type molecule and tungsto(molybdo)phosphoric heteropolyacids (HPA) (HPA = H₃PMo₁₂O₄₀ and H₃PW₁₂O₄₀, abbreviated as HPMo₁₂ and HPW₁₂, respectively) of the Keggin structure as the inorganic component, were prepared and characterized by π-A isotherms, UV-vis absorption and luminescence spectra, low-angle X-ray diffraction, scanning tunneling microscopy and surface photovoltage spectroscopy. Our experimental results indicate that stable, well-defined and well-organized Langmuir and LB films have been formed in pure water and heteropolyacid subphase. They typically have a highly organized lamellar structure in which a monolayer of HPA is most likely embedded inside the OMA molecular space formed by long chains of PBu₃. Luminescence spectra of these hybrid LB films show that HPMo₁₂ and HPW₁₂ can enhance the emission of OMA to some extent. These LB composites show good photovoltage responses and a photovoltage of 79 μV can be obtained for the OMA/HPMo₁₂ system when it is excited by light. The monolayer LB films on ITO wafer can also display interesting electrical conductivity.     

Preparation, luminescent, structural and electrical properties of Langmuir-Blodgett films of new organomercurial acetylide complex/heteropolyoxometalate hybrid composites

A new family of organometallic/inorganic nanohybrid Langmuir-Blodgett (LB) films consisting of rigid-rod organomercury acetylide complex (OMA) as the π-conjugated organometallic composite and heteropolyacid salts MPA (MPA = K₃PMo₁₂O₄₀, K₅BW₁₂O₄₀, Na₅IMo₆O₆₂) of the Keggin and Anderson structures as the inorganic composite, were prepared and characterized by π−A isotherms, UV−Vis absorption spectra, fluorescence spectra, scanning tunneling microscopy, atomic force microscopy imaging and low-angle X-ray diffraction. Our experimental results indicate that steady Langmuir and LB films are formed in pure water and heteropolyacid salt subphases. Luminescence spectra of hybrid LB films show that MPA can quench the emission of OMA to some extent. These alkynylmercury(II) based LB films display interesting electrical conductivity behavior. They all show decent electrical conductivity, and the tunneling current amounts to ±100 nA when the voltage is set at ±3 ∼ ±5 V.     

稀土三酞菁夹心化合物混合LB膜的研究

将不对称三明治型夹心化合物(Pc)Dy[Pc(OC₈H₁₇)₈]Dy[Pc(OC₈H₁₇)₈]与硬脂酸混合成膜，表面压-面积（π-A）曲线表明形成了稳定的单层膜，由透射电子显微镜（TEM）观察,表明硬脂酸的加入有效地改善了分子的聚集行为，分子形成了取向高度有序的结构。用紫外-可见光谱、偏振紫外可见光谱、低角X射线衍射等对LB膜进行了研究，发现该取代稀土三酞菁分子在气/液界面上长链向上伸展，分子之间均以面对面（face-to-face）排列，以一边接触（edge-on）方式取向,大环平面与基片夹角约为52°，每层厚度为2.41 nm。     

Preparation and characterization of 5,10,15,20‐tetraphenylporphyrin Langmuir films for gas chemsensor applications

In this work is reported the preparation and characterization of 5,10,15,20‐tetraphenylporphyrin (H₂TPP) films at the water‐air interfaces. The surface pressure‐area isotherms (π‐A) and UV‐Vis spectroscopy were used to investigate the effect of the spreading methods and parameters on the porphyrin monolayer formation. Also, Langmuir‐Blodgett (LB) and Langmuir‐Schaefer (LS) films were deposited onto glass substrates in order to study the conformation changes in porphyrin molecular packing. Quartz crystal microbalance (QCM) was utilized as the active solid substrate for the development of the NO₂ gas sensor based on the H₂TPP molecular films. The results of π‐A curves have clearly shown the significant contribution of the preparation methods and processing parameters on the conformation of porphyrin molecular films. The UV‐Vis spectroscopy results using polarized absorption dichroism have indicated different molecular packing for porphyrin films deposited by LB and LS methods, with relative tilted angles of 50° ± 5° and 35° ± 5°, respectively. Moreover, the QCM response has given strong evidence that H₂TPP porphyrin molecular films have performed as NO₂ chemsensor. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis and Characterization of H3PW12O40 and H3PMo12O40 Nanoparticles by a Simple Method

In this study H₃PW₁₂O₄₀·9H₂O and H₃PMo₁₂O₄₀·6H₂O (HPA) particles were changed into nano forms by heat-treatment in an autoclave as a simple, repaid, inexpensive and one step method. The particle size of these nanoparticles was around 25 nm. The as-synthesized nanostructures were characterized by dynamic light scattering, X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy and inductively coupled plasma analyzer. Thermal stability of nanoparticles was surveyed by thermal gravimeter analyse. Acidity of prepared nanoparticles was investigated by pyridine adsorption method. Results showed rising acidity by declining particle size of HPA.     

Arrhenius constants for the reactions of ozone with ethylene and acetylene

The kinetics of ozonation of C₂H₄ and C₂H₂ have been studied in the gas phase from ?40 to ?95°C (C₂H₄) and +10 to ?30°C (C₂H₂). The O₃ concentrations were near 10^?4 M, and the hydrocarbons were present in 2- to 25-fold excess. A few experiments with propylene were also carried out. The reactions were followed by observing the rate of decay of O₃ absorption at 2537 Å. Reaction stoichiometries and effects of added O₂ were investigated. The second-order rate constant for C₂H₄ was log k(M^?1 sec^?1) = (6.3 ± 0.2) – (4.7 ± 0.2)/θ (θ = 2.3RT). The rate was independent of the presence of excess O₂. Rate measurements for C₃H₆ were less accurate because of aerosol interference. Combined with room temperature measurements of other workers, the C₃H₆ rate constant was log k(M^?1 sec^?1) = (6.0 ± 0.4) – (3.2 ± 0.6)/θ. The C₂H₂ rate constant was log k(M^?1 sec^?1) = (9.5 ± 0.4) – (10.8 ± 0.4)/θ. In the case of C₃H₆ the major product was propylene ozonide. Ethylene did not yield the ozonide, and the products of the O₃–C₂H₄ and O₃–C₂H₂ reactions were not identified. Pre-exponential factors for the olefin reactions are consistent with a five-membered ring transition state formed by 1,3 dipolar cycloaddition of O₃. For C₂H₂, however, the much higher observed A factor suggests a different mechanism. Possible transition states for the O₃–C₂H₂ reaction are discussed.