修饰Langmuir-Blodget膜法制备聚(3,4-亚乙基二氧噻吩)薄膜结构和导电性能的研究

采用修饰Langmuir-Blodget(LB)膜法以二十烷酸(AA)LB膜为模板,通过3,4-亚乙基二氧噻吩(EDOT)单体在LB膜亲水基团间聚合,制备了二十烷酸/聚(3,4-亚乙基二氧噻吩)(AA/PEDOT)复合LB膜.UV-Vis、FTIR和XPS分析表明EDOT在多层膜中有效聚合,生成了PEDOT导电聚合物;X射线衍射(XRD)和二次离子质谱(SIMS)分析表明薄膜具有较好的层状有序结构,进一步研究发现EDOT在AA多层膜中的聚合破坏了原有LB膜的有序性,这可能与聚合过程对层状结构产生的破坏作用有关;采用四探针仪及半导体测试仪研究了薄膜导电性能,发现AA/PEDOT多层膜的电导率随处理时间的变化产生突变,这与多层膜中导电通道的"逾渗"有关,在有效导电网络连通后电导率发生了突变.测试结果还表明AA层和PEDOT层之间具有较为明显的界面,PEDOT显示出较好的定域性,薄膜具有很好的层状有序结构.     

Study on Conductivity Properties of PEDOT Prepared through a Modified LB Film Method

Adopting LB film method, an arachidic acid (AA)/PEDOT multilayer LB film was chosen, and polymerized EDOT monomers in hydrophilic group of LB to prepare arachidic acid (AA)/PEDOT multilayer LB film. UV‐Vis, FT‐IR and XPS analyses implied that EDOT was effectively polymerized in film, and thus PEDOT conducting polymer was produced. Analyses of XRR and SIMS indicated that film had a well‐arranged lamella structure, and further research showed that polymerization of EDOT in AA film destroyed the orderliness of the original LB film. This phenomenon could be related to the destructive effect of polymerization on layered structure. We used four‐point probe and semiconductor instrument to study the conductivity property of the film, and observed that the conductivity of AA/PEDOT film had sudden changes with the processing time of changes in effective conduction network. That was caused by "permeability" in conducting channel of multilayer film. The test results also indicated that the conductivity of AA/PEDOT film was obviously better than that of spin‐coating PEDOT/PSS film or that of ODA‐SA/PEDOT‐PSS film, which was due to the higher π structure of PEDOT structure and ordered film structure.     

Surface-enhanced spectroscopy of Langmuir—Blodgett films of N-octyl,N′-isobutyl-3,4:9,10-perylene-bis(dicarboximide)

The infrared, resonant Raman and surface-enhanced resonant Raman spectra of N-octyl, N′-isobutyl-3,4:9,10-perylene-bis(dicarboximide) (PBDC) were obtained and the aggregation of PBDC molecules was studied using surface-enhanced fluorescence. Langmuir—Blodgett (LB) films of the neat dye as well as mixed layers with arachidic acid, were prepared and transferred to glass slides and surface-enhanced active surfaces for spectroscopic characterization. A strong red shifted excimer emission was characteristic of LB layers of the neat material and of the thin solid films formed by dipping a glass slide into a solution containing the dye and a volatile solvent. However, using mixed LB monolayers of PBDC and arachidic acid, the surface-enhanced fluorescence of the monomer was observed. The surface-enhanced scattering was measured for both neat and mixed LB layers.     

四硫代富瓦烯及其CT复合物导电LB膜

通过Langmuir-Blodgett（LB）技术制备导电性有机超薄膜近年来受到了广泛的关注，导电LB膜的膜材料主要是含有电子受体77’，8，8’一四氨基二亚甲基本自（TCN则的电行转移（CT）复合物间以及给体分子特别是四流代宫瓦烯衍生物［‘刮.在以前的工作中，我们曾报导了四等基硫四硫     

Synthesis and Structure of PEDOT Prepared through a Modified LB Film Method

Adopting LB film method, an arachidic acid (AA)/PEDOT multilayer LB film and polymerized EDOT monomers in hydrophilic group of LB were chosen to prepare the arachidic acid (AA)/PEDOT multilayer LB film. UV-Vis, FT-IR and XPS analyses implied that EDOT was effectively polymerized in film, and thus PEDOT conducting polymer was produced. Analyses of XRR and SIMS indicated that the film had a well-arranged lamella structure, and further research showed that polymerization of EDOT in AA film destroyed the orderliness of the original LB film. This phenomenon could be related to the destructive effect of polymerization on the layered structure. We used four-point probe and semiconductor instrument to study the conductivity property of the film, and observed that the conductivity of AA/PEDOT film had sudden changes with the changes of processing time in an effective conduction network, which was caused by "permeability" in conducting channel of multilayer film. The test results also indicated that the conductivity of AA/PEDOT film was obviously better than that of spin-coating PEDOT/PSS or ODA-SA/PEDOT-PSS film due to the higher π structure of PEDOT structure and ordered film structure.     

稀土螯合物发光体LB膜的研究(I)

稀土有机配合物的发光研究近年来取得了可喜的近展.铕(Ⅲ)、铽(Ⅲ)、钐(Ⅲ)与β-二酮(β-dik),三正辛基氧化膦(TOPO)所形成的螯合物,以及它们的硝酸盐与邻菲咯啉(Phen)所形成的螯合物都是高光效的发光体,有广阔的应用前景,在某些方面已获得应用.如能把这些具有发光功能的稀土螯合物组装成有序的分子组合体,则很可能在分子光学技术,光电子技术等领域发挥重要作用.如何组装?本文用LB 膜技术,通过交替成膜或混     

Dicyanopyrazine-linked porphyrin Langmuir-Blodgett films

We investigated the influence of arachidic acid/cadmium dication (AA/Cd(2+)) as a transfer promoter for the deposition of dicyanopyrazine-linked porphyrin (2-DCPP) Langmuir-Blodgett (LB) films on both hydrophobic and hydrophilic substrates. In the case of LB deposition on a hydrophilic substrate, the presence of AA/Cd(2+) does not improve 2-DCPP LB deposition. The poor transfer in the case of the hydrophilic surface is believed to be due to 2-DCPP not wetting the surface during the down-stroke deposition, and this is not improved by the transfer agent. However, on a hydrophobic substrate, deposition of 2-DCPP is significantly improved by the presence of AA/Cd(2+). Comparison of the UV-visible spectrum of a 2-DCPP LB film with that of 2-DCCP dissolved in chloroform reveals that the Soret and Q bands for the 2-DCPP LB film are broadened and red-shifted due to aggregation of porphyrin rings in the LB film. UV-visible spectral changes and ellipsometry as a function of the number of deposition layers suggest continuous transfer of 2-DCPP/AA onto the hydrophobic substrate and reproducibility in the deposition process. The Soret and Q bands of the 2-DCPP LB film upon acid vapor exposure have also been investigated, and these measurements may have chemical sensor applications.     

2-硝基-5-(N-甲基-N-十八烷基)氨基苯甲酸多层膜的制备和性质

用2-硝基-5-(N-甲基-N-十八烷基)氨基苯甲酸(NMOB)和花生酸制备了200层的交替多层膜, 测得其二次谐波信号强度与NMOB层数的平方成正比。论文着重讨论了NMOB的Y型膜和它与花生酸的交替膜中的取向, 并对两者之间的不同作了初步的解释。     

不含亲水基团的偶氮苯衍生物L-B膜的制备和性质研究

本文合成了具有一定结构特点的偶氮苯的衍生物, 以元素分析和^1HNMR鉴定了B产物的组成和结构。采用L-B技术制备了其多层L-B膜, 以紫外可见光谱研究了膜中分子的聚集状态和膜的纵向均匀性; 以偏振紫外确定了膜中分子偶氮基的取向; L-B膜的小角度X射线衍射结果表明膜具有层状有序的周期性结构。     

Deposition and characterization of Langmuir‐Blodgett films of cadmium arachidate/SWCNTs composites

The incorporation of single‐wall carbon nanotubes (SWCNTs) in cadmium arachidate film by means of the Langmuir‐Blodgett (LB) technique was investigated as a function of arachidic acid/SWCNT mass ratio at the air/water interface and in Langmuir‐Blodgett films. The behaviour at the air/water interface shows that SWCNTs act as an independent phase with respect to the cadmium arachidate. Deposition conditions are optimized when the weight ratio between the arachidic acid (AA) and SWCNTs is in the range 0.018:1 to 1:1. The general order of the LB multilayered structure was destroyed by the progressive density increase in SWCNT quantity as evidenced by X‐ray reflectivity (XRR) analysis. Scanning electron microscopy images indicated that when a multilayered structure was formed its layers consisted of SWCNT bundles stacked one over the other. Copyright © 2006 John Wiley & Sons, Ltd.     

Study of assembly of arachidic acid/LDHs hybrid films containing photoactive dyes

Hybrid monolayers formed with an floating arachidic acid (AA) anions monolayer binding with a densely packed layered double hydroxides (LDHs) monolayer at an air/LDHs suspension interface has been studied by pi-A isotherms and TEM images. An ordered multilayer film of AA/LDHs has been fabricated by Langmuir-Blodgett technique on various substrates. The photoactive dyes (methyl orange, MO, and Congo red, CR) can be incorporated into the galleries of LDHs in the AA/LDHs hybrid LB film by an ion intercalation method. The results of FTIR and UV-vis absorption spectra can approve the formation of AA/LDHs/dyes composite films. In addition, UV-vis absorption spectra and LAXRD analyses also provide evidence for the good vertical uniformity and stable layered periodic structure of AA/LDHs/dyes films. More interestingly, it was found that the dye molecules intercalated can be induced by a positively charged LDHs sheet to align in a special orientation and form different aggregates: MO molecules form sandwich H-type aggregates, while CR molecules form head-to-tail J-type aggregates. On the basis of these data, a possible model of the AA/LDHs/dyes composite films was proposed. Also, the dye molecules incorporated into AA/LDHs films exhibit excellent configuration stability under the irradiation of UV light because the LDHs matrix offers a more rigid and constrained environment for them.     

Maximum withdrawal speed for Langmuir-Blodgett film deposition of arachidic acid

The maximum withdrawal speed of Langmuir-Blodgett (LB) film deposition of arachidic acid (AA) was investigated. The quality of LB deposited film was determined by the transfer ratio (TR), together with measurements of surface roughness using atomic force microscopy (AFM). A Langmuir mini-trough was used to provide the surface pressure versus molecular area (pi-A) curves and a flow visualization technique was applied to estimate the dynamic contact angles and to observe the fluid motion. The effects of hydrophobic and hydrophilic substrates, pH and the addition of four different ions, i.e., K+, Ba2+, Cd2+, and Al3+, on the withdrawal speed were examined. The "transition point" from liquid to solid states on the pi-A curve provided a clear indication of the maximum withdrawal speed. The lower the transition point, the higher was the maximum withdrawal speed. Stable deposition was possible only if the pH of the solution was maintained in a narrow range. The observation of dynamic contact angles and fluid motion, particularly the movement of air-liquid interface, was consistent with previous findings. Owing to the "soap effect" of the divalent ions Ba2+ and Cd2+, the maximum speed for successful LB film deposition without significant water entrainment could be extended substantially with the addition of divalent ions.     

酞菁铜化合物LB膜的制备及结构形态研究

利用LB技术研究了带有4个长碳氢链的酞菁铜化合物(CuC12Pc)的单分子膜及它与十八胺(ODA)、二十酸(AA)的混合LB膜的聚集结构形态. 结果表明这种酞菁铜化合物在气液界面上可以形成比较稳定有序的双层Langmuir膜, 且可以转移质量较好的多层LB膜. 利用原子力显微镜(AFM)研究了酞菁铜分子的聚集体结构, 发现CuC12Pc/AA混合膜表现为网状的聚集结构, 而CuC12Pc/ODA混合膜形成长岛颗粒状聚集, 并结合UV-Vis吸收光谱讨论了酞菁铜分子形成不同聚集结构的原因.     

液晶聚合物的单层与Langmuir-Blodgett膜

系统研究了手性液晶聚硅氧烷和光致变色液晶聚硅氧烷两个毓的侧链液晶聚合物在空气/水界面的单层行为和Langmuir-Blodgett(LB)膜沉积特性,对LB膜结构与存在的聚集现象进行了系统的表征,并初步探讨了LB膜中液晶聚合物表现的功能性。     

An ensemble and single-molecule fluorescence microscopy investigation of phase-separated monolayer films stained with Nile Red

Phase-separated Langmuir-Blodgett monolayer films prepared from mixtures of arachidic acid (C19H39COOH) and perfluorotetradecanoic acid (C13F27COOH) were stained via spin-casting with the polarity sensitive phenoxazine dye Nile Red, and characterized using a combination of ensemble and single-molecule fluorescence microscopy measurements. Ensemble fluorescence microscopy and spectromicroscopy showed that Nile Red preferentially associated with the hydrogenated domains of the phase-separated films, and was strongly fluorescent in these areas of the film. These measurements, in conjunction with single-molecule fluorescence imaging experiments, also indicated that a small sub-population of dye molecules localizes on the perfluorinated regions of the sample, but that this sub-population is spectroscopically indistinguishable from that associated with the hydrogenated domains. The relative importance of selective dye adsorption and local polarity sensitivity of Nile Red for staining applications in phase-separated LB films as well as in cellular environments is discussed in context of the experimental results.     

J-aggregation and its characterization in Langmuir-Blodgett films of merocyanine dyes

Langmuir-Blodgett (LB) films are constructed by successively transferring monomolecular layers formed at the air-water interface onto solid substrates. One of the advantages of the LB technique in fabricating molecular aggregates lies in the fact that it can employ various kinds of molecules by mixing them at the air-water interface. The mixed system may exhibit new properties that are not observed for individual components. This method would be useful, for example, in the studies of the formation and control of the J-aggregates of functional dyes that attract attention both in science and technology. In this paper, I review this subject mainly based on our recent results in merocyanines. LB films of merocyanine dyes, mixed with arachidic acid (C(20)), exhibit J-aggregate formation and have been serving as typical systems in revealing the physical and structural aspects of nanosized molecular aggregates constructed as monolayers. In the case of LB films of a merocyanine dye having benzothiazole as donor nucleus (abbreviated as DS), electron spin resonance (ESR) spectroscopy has been successful in determining the characteristic in-plane orientation of dye molecules with respect to the dipping direction, which led to the discovery of the flow orientation effect during the dipping process of LB films as the origin of optical dichroism often observed in LB films. In this article, after an introduction of ESR spectroscopy, three major topics on the merocyanine J-aggregation and its characterization in mixed films are discussed. The first topic is the observation and control of the size of J-aggregates in the dilution limit of dyes in arachidic acid matrix for a methyl-substituted DS (6-Me-DS). Dependence of atomic force microscopy (AFM) patterns on the molar ratio allows the identification of dye domains. J-band optical peak analysis based on the Kuhn's extended dipole model, supplemented by a novel application of femtosecond pump-probe optical spectroscopy, yields the size of the J-aggregates of 10(3). The second topic is the control of the J-band peak wavelengths by mixing two different kinds of dye molecules. The first case is the mixture of a J-forming 6-Me-DS and non-J-forming merocyanine analog, DO with benzo-oxazole instead of benzothiazole of DS. The second case is the mixture of both J-forming dyes but with different J-band peak positions, 6-Me-DS and another analog of 5-Cl-DS. The optical peak shifts depending on the molar mixing ratio will be presented. The last topic is related to the elucidation of electronic states of dye molecules in the J-aggregates. Light-induced ESR (LESR) of DS films with stable isotope ((15)N or (13)C)-substituted dyes provide clear evidence for the photoinduced charge transfer by the detection of hyperfine structures. Moreover, infrared (IR) spectroscopy of (13)C-enriched dye identifies the IR absorption peak of the relevant carbon in the chromophore. The results give evidence for the enhanced intramolecular charge transfer of dyes in the J-aggregates compared with an isolated merocyanine composed of donor and acceptor moiety. Lastly, the Cl attachment in 5-Cl-DS leads to a significant enhancement of the nitrogen hyperfine coupling in the LESR spectra. These examples and others demonstrate the potential of LB films of merocyanines in the studies of the nanosized molecular aggregates in monolayer assemblies.     

由组分可控的LB膜前驱物法制备Y2O3稳定立方相ZrO2的超薄陶瓷膜

由有机LB膜技术发展了一种制备组分、厚度可控的无机超薄陶瓷膜的方法.以Zr、 Y的β-二酮络合物的作为"表面离子"代替传统的亚相离子,沉积它们与花生酸的混合LB膜.并将它作为前驱物,经臭氧处理和热处理,成功制得了Y2O3稳定的立方相ZrO2超薄膜(YSZ).用X射线衍射(XRD)、 X射线光电子能谱(XPS)等手段研究了YSZ薄膜的相结构和其组成.结果表明,超薄陶瓷膜中Zr与Y的含量比率控制得很好,且形成Y2O3稳定的立方相ZrO2.说明这种方法可以成功地用来制备组分和膜厚均可控的纳米陶瓷膜.     

修饰LB膜法制备的PEDOT薄膜对HCl气体气敏性的影响

以二十烷酸(AA)LB膜为模板, 通过3,4-乙烯二氧噻吩(EDOT)单体在LB膜亲水基团间聚合, 采用垂直拉膜方式在叉指电极上制备了不同层数的AA/PEDOT膜, 并对HCl气体在AA/PEDOT复合LB膜中的作用进行研究, 结果表明, 膜厚、处理温度、拉膜膜压对AA/PEDOT复合LB膜的HCl气体敏感性能有不同程度的影响. 在较小气体体积分数范围(20～60 μL/L)内, AA/PEDOT多层有序膜对气体表现出非线性响应特性, 而在较高浓度范围内则表现出线性响应特性. AA/PEDOT复合LB膜对30 μL/L HCl气体的响应时间约为20 s, 远快于普通PEDOT旋涂膜(约为80 s), 同时在膜压达到45 mN/m时, AA/PEDOT膜的敏感性能反而下降. 敏感机理解释为电子在PEDOT共轭系统和氧化性气体间的转移.     

Single molecular detection of a perylene dye dispersed in a Langmuir-Blodgett fatty acid monolayer using surface-enhanced resonance Raman scattering

The Langmuir-Blodgett (LB) monolayer technique was used to fabricate single molecule LB monolayer containing bis(phenethylimido)perylene (PhPTCD), a red dye dispersed in arachidic acid (AA) with an average doping of 1 molecule per microm2. The monolayer was transferred onto Ag island films to obtain spatially resolved surface-enhanced resonance Raman scattering (SERRS) spectra. The mixed LB monolayers were fabricated with a concentration, on average, of 1, 6, 19 and 118 PhPTCD molecules per microm2 in AA. The AA provides a two-dimensional host matrix whose background signal does not interfere with the detection of the probe molecule's SERRS signal. The properties of the single molecule detection were investigated using micro-Raman with a 514.5-nm laser line. The Ag island surfaces coated with the LB monolayer were mapped with spatial steps of 3 microm and global chemical imaging of the most intense SERRS band in the spectrum was also recorded. The SERRS and surface-enhanced fluorescence (SEF) of the neat and single molecule LB monolayer were recorded in a temperature range from liquid nitrogen to + 200 degrees C. Neat PhPTCD LB monolayer spectra served as reference for the identification of characteristic signatures of the single molecule behavior. The spatial resolution of Raman-microscopy experiments, the multiplicative effect of resonance Raman and SERRS, and the high sensitivity of the new dispersive Raman instruments, allow SERRS to be part of the family of single molecular spectroscopies.     

Morphological investigation of hybrid Langmuir-Blodgett films of arachidic acid with a hydrotalcite/dendrimer nanocomposite

A hydrotalcite clay/dendrimer nanocomposite prepared by the ionic exchange process was adsorbed from suspension of the nanocomposite on a Langmuir monolayer of arachidic acid at the air/water interface, followed by compressing and transferring onto an arachidic acid monolayer Langmuir-Blodgett (LB) film on mica. For comparison, the hydrotalcite-adsorbed hybrid film was also prepared. The morphology of hydrotalcite and the nanocomposite studied by transmission electron microscopy indicated the layered structures with respectively 1.2 +/- 0.3 and 3.2 +/- 0.5 nm repeating distances. The hybrid Langmuir films displayed the occupied surface area of 0.24 nm2 for both hydrotalcite and the nanocomposite. The formation of hybrid Langmuir films was confirmed by Brewster angle microscopy. Atomic force microscopic images of hybrid LB films revealed the formation of plateau domains with the height difference of 6 nm for hydrotalcite and 12 nm for the nanocomposite and the presence of dendrimers adsorbed on the clay surface of the nanocomposite.