Ftir Studies on LB Film of Amphiphile with Schiff Base as Headgroup and Its Copper Complex

Two different ways to form monolayers and LB films (surface film and subphase film) of the complex have been used, where a novel amphiphile containing Schiff base as a headgroup was used as a ligand. the monolayer behavior at the air/water interface was characterized by π-A isotherms and two-dimensional molecular orientation of alkyl chains in LB films and thermal stability were measured by polarized and variable temperature FTIR transmission spectra, indicating that the LB film of the novel amphiphile and its copper(II) complex are very stable as well as stearic acid. Because incorporating the metal ion into the monolayer makes it more condensed, thermal stability of the LB film was enhanced. as can be compared from their structure and properties, subphase films are superior to surface films.     

FT-SERS研究核脂两亲分子单分子膜的分子识别

核酸中通过多重氢键发生的互补碱基之间的分子识别是自发产生的并具有高度的选择性，是遗传信息存储和复制的高效机制之一。近年来由含核酸碱基的类脂形成的表面单层体系，模拟ＤＮＡ复制过程中的互补碱基通过多重氢键而发生的分子识别过程已引起广泛注意［１－２０］，已...     

Structure and Orientation of 1-Hydroxyl-5-Hexadecyloxy-Naphthalene LB Films Studied By UV-VIS and FTIR Spectroscopy

Ultraviolet-visible (UV-Vis), infrared transmission, and reflection absorption(RA) spectra have been measured for one-and multi-monolayer Langmuir-Blodgett(LB) films of C₁₆H₃₃30Naph(1,5)OH at various temperature to investigate dependencies of the aggregation and phase transitions on the number of monolayers. The UV-vis spectra of the LB films have revealed that the C₁₆H₃₃ONaph(1,5)OH forms aggregates in the LB film. From the temperature dependence of UV-vis absorption spectra, it is clear that the aggregate is gradual converted to monomer upto 80 °C. A comparison of the infrared transmission and RA spectra reveals that the hydrocarbon chains are tilted considerably in the LB film. As for the naphthalene ring part, the result suggest that the ring plane is oriented approximately perpendicular to the substrate surface. The Temperature dependence of infrared transmission spectra have been measured for 1-, 3-, and 11-monolayer LB films to investigate dependence of phase transitions on the number of monolayers. These observations show that the one-monolayer LB films does not have a clear order-disorder transition, while the three-and eleven-monolayer films have a phase transition near 60 °C. Therefore, it seems that the title angles of both the alkyl chain and chromophore part change largely concomitantly with the conversion from the aggregate to the monolayer.     

Fourier Transform Infrared Transmission Spectral Study on the Thermal Stability of Multilayer Langmuir-Blodgett Film of Stearic Acid

Fourier transform infrared (FTIR) transmission spectra at elevated temperatures of the 21-layer LB film of stearic acid have been recorded to study the thermal-induced order-disorder transition of the film. The transition was found to take place around 65°C (T _c), which results in the introduction of gauche conformers into the ordered zigzag alkyl chains, and the transformation of the trans dimers of the carboxylic groups to the cis ones while both configurations coexist below T _c. It was found that the mobility and the orientational disorder of the alkyl chains begin to increase before their conformational disorder occurs., The temperature-dependent spectra of the bulk stearic acid were also measured for comparison. The cyclic thermal treatment of the LB film indicates that the structural changes caused by the order-disorder transition is largely irreversible, although the conformation of the alkyl chains and the dimeric configuration of the carboxylic groups return to the corresponding states at room temperature.     

红外透过、反射吸收光谱研究手性液晶(M1)LB膜的结构与取向

利用ＦＴＩＲ光谱研究了一种手性液晶化合物（Ｍ１）ＬＢ膜的结构与取向,该化合物可以形成稳定的单层与多层膜。手性分子中,芳香环平面向于垂直基片表面,分子中的烷基链部分则与基底表面法线方向成一定的角度。     

1-羟基-5-十二烷氧基-萘LB膜结构和取向的光谱研究

用红外透射,反射光谱及紫外可见吸收光谱方法研究了１－羟基－５－十二烷基－萘ＬＢ膜及溶液状态下的结构,分子取向。研究结果表明分子在溶液中主要是以单体形式存在;在ＬＢ膜中是以聚集体形式存在。     

不同预淀积层银膜表面等离子激元波的辐射效率

测量了棱镜／ＬＢ膜／银膜／空气，棱镜／银膜／空气，棱镜／银膜／空气三种结构在衰减全反射条件下激发的表面等离子激元波由于银膜－空气界面粗糙度而散射以空气中的辐射效率，同时，由散射光强分布计算出表面度粗糙度参数随横向相关长度σ和表面波纹深度δ，再由σ和δ计算出理论辐射效率，理论与实验结果相符合。     

不同衬底银膜表面等离子激元波的辐射效率

不同衬底银膜表面等离子激元波的辐射效率邓里文王恭明（复旦大学物理系上海２００４３３）ＥｆｉｃｉｅｎｃｙｏｆＥｍｉｓｉｏｎｆｒｏｍＳｕｒｆａｃｅＰｌａｓｍｏｎＷａｖｅｓｆｏｒＤｉｆｅｒｅｎｔＳｔｒｕｃｔｕｒｅｓｏｆＡｇＦｉｌｍｓＤｅｎｇＬｉｗｅｎ，Ｗａ...     

受抑全反射的微波实验研究

首先回顾了受抑全反射的历史背景和广泛的应用价值,然后分析了受抑全反射的理论机制,得到相应的倏逝波透射率公式;并且建立了一套简单的实验装置系统,研究了受抑全内反射(FTIR)的透射率和空气薄膜厚度、偏振方向之间的关系.所得结果和理论分析符合的很好.     

新型混合脂质体的制备及其与药物的分子识别研究

设计、合成了含核酸碱基的双亲化合物N6-十四酰基-9-辛基腺嘌呤三甲基溴化铵;用目标化合物和卵磷脂制备混合脂质体受体。分别研究了受体与巴比妥酸、核黄素药物在混合脂质体亲脂区通过互补氢键进行的分子识别。紫外可见光谱研究表明,底物巴比妥酸在258nm的吸收峰,核黄素在222nm,264nm的吸收峰随时间的延长而逐渐降低,这种减色作用归因于脂质体内的巴比妥酸和核黄素在亲脂区分别与双亲化合物上的腺嘌呤形成了氢键。     

Langmuir and Langmuir-Blodgett (LB) films of tetrapyridyl metalloporphyrins

We report on the formation of Langmuir films of 5,10,15,20-tetra(4-pyridyl) 21H,23H-porphine, hereafter named tetrapyridyl porphyrins with distinct central ions (2H⁺, Zn²⁺, Cu²⁺, Ni²⁺). The films were characterized with surface pressure and surface potential isotherms and in situ UV-vis absorbance. The measurements indicated strong aggregation of porphyrin monomers at the air-water interface, with a red shift of the Soret band in comparison with the spectrum obtained from CHCl₃ solutions. The shift was larger for the non-substituted H₂TPyP, and depended on the metal ion. Significantly, aggregation occurred right after spreading of the Langmuir film, with no further shifts in the UV-vis spectra upon compression of the film, or even after transferring them onto solid substrates in the form of Langmuir-Blodgett (LB) films. The buildup of LB films from H₂TPyP and ZnTPyP was monitored with UV-vis spectroscopy, indicating an equal amount of material deposited in each deposition step. Using FTIR in the transmission and reflection modes, we inferred that the H₂TPyP molecules exhibit no preferential orientation in the LB films, while for ZnTPyP there is preferential orientation, with the porphyrin molecules anchored to the substrate by the lateral pyridyl groups.     

5,10,15,20-四-(4-十六烷基吡啶基)卟啉LB膜结构的研究

研究了两亲性卟啉５,１０,１５,２０－四－（４－十六烷基吡啶基）卟啉溴化物在气－液界面上的成膜性能,制备了其ＬＢ膜。用扫描隧道显微镜和ＵＶ－Ｖｉｓ光谱,荧光光谱,小角Ｘ射线衍射等实验方法研究了ＬＢ膜的形貌和卟啉大环分子在ＬＢ膜中的排列、取向和分子间的相互作用。结果表明,制备的ＬＢ膜结构均匀,性能稳定,在ＬＢ膜内,脂肪链并不是直立的,卟啉分子大环几乎平躺在基片上。     

Molecular resolution of Langmuir-Blodgett monolayers on tungsten diselenide by scanning tunneling microscopy

Langmuir-Blodgett (LB) monolayers of 22-tricosenoic acid deposited on layered tungsten diselenide (WSe₂) have been investigated by Scanning Tunneling Microscopy (STM) in air. Reproducible molecular scale imaging of extended areas (16×16 nm) of the films was possible over more than two months after preparation. This indicates a high stability of the films on this type of polar substrates. The two-dimensional lattice of the organic film is incommensurate to the lattice of the WSe₂ substrates. The STM experiments also indicate that the tip partially penetrates the organic film without destroying the film structure.     

A spectroscopic study of water-soluble pyronin B and pyronin Y in Langmuir-Blodgett films mixed with stearic acid

Mono and multilayer of water-soluble pyronin B (PyB) and pyronin Y (PyY) mixed with stearic acid (SA) have been incorporated in Langmuir-Blodgett (LB) films. The surface pressure-area (π-A) isotherm studies pointed out that pure PyB and PyY are incapable of forming stable films at air-water interface and collapsed readily at low surface pressures. However, mixture of PyB or PyY with SA easily formed stable films at the air-water interface and they were easily transferred onto solid substrates. The average area per molecule of mixed films of PyB and PyY at the air-water interface was observed to decrease with increasing concentrations of PyB and PyY. The spectroscopic characteristics of PyB and PyY in chloroform, in SA containing chloroform and in LB films have also been investigated by using absorption and steady-state and time-resolved fluorescence spectroscopy techniques. The morphology of the LB film surfaces has been characterized by using atomic force microscopy (AFM).     

Structural Study on 5-(Dodecyloxy)-1-((6-Trimethylammonio)Hexyl)oxy)Naphthalene—Sodium Dextran Sulfate Langmuir-Blodgett Film Through Fourier Transform Infrared Spectroscopy

The Fourier transform infrared transmission (FTIR-T) and attenuated total reflection (ATR) spectra of the 5-(dodecyloxy)-1-((6-(trimethylammonio)hexyl)oxy)naphthalene — sodium dextran sulfate composite LB films deposited under the surface pressure of 30 mN/m have been recorded and spectral assignments made. By means of polarization techniques and with the application of the uniaxial and biaxial orientation models, the orientation characteristics of the long hydrocarbon chains and the = C-O linkage in the LB films have been investigated, giving rise to the detailed information of the arrangement of molecular fragments in the 1-SDS composite LB films.     

Fundamental studies of molecular depth profiling and 3D imaging using Langmuir-Blodgett films as a model

Molecular depth profiling and three-dimensional imaging using cluster projectiles and SIMS have become a prominent tool for organic and biological materials characterization. To further explore the fundamental features of cluster bombardment of organic materials, especially depth resolution and differential sputtering, we have developed a reproducible and robust model system consisting of Langmuir-Blodgett (LB) multilayer films. Molecular depth profiles were acquired, using a 40-keV C₆₀⁺ probe, with LB films chemically alternating between barium arachidate and barium dimyristoyl phosphatidate. The chemical structures were successfully resolved as a function of depth. The molecular ion signals were better preserved when the experiment was performed under cryogenic conditions than at room temperature. A novel method was used to convert the scale of fluence into depth which facilitated quantitative measurement of the interface width. Furthermore, the LB films were imaged as a function of depth. The reconstruction of the SIMS images correctly represented the original chemical structure of the film. It also provided useful information about interface mixing and edge effects during sputtering.     

Molecular structure of polystyrene at Air/Polymer and Solid/Polymer interfaces

IR-visible sum-frequency generation (SFG) spectroscopy has been used in a total internal reflection geometry to study the molecular structure of polystyrene (PS) at PS/sapphire and PS/air interfaces, simultaneously. The symmetric vibrational modes of the phenyl rings dominate the SFG spectra at the PS/air interface as compared to the antisymmetric vibrational modes at the PS/sapphire interface. This indicates approximately parallel orientation of the phenyl rings at the PS/air interface while nearly perpendicular orientation at the PS/sapphire interface, with respect to the surface normal.     

电介质膜对受抑全内反射结构中古斯-汉欣位移的增强

受抑全反射结构中,反射光束和透射光束的古斯汉欣(Goos-Hanchen)位移同时存在,对称双棱镜结构的受抑全反射古斯汉欣位移通常只有波长量级,在实验中很难测量。计算了在入射角大于棱镜与空气界面的临界角小于棱镜与薄膜界面临界角时,镀有电介质膜的对称双棱镜的受抑全反射过程中入射光束的反射系数和透射系数的复数表达式。利用稳态相位法计算得出透射光束和全反射光束的古斯汉欣位移。结果表明,反射光束和透射光束古斯汉欣位移量相同,与入射角大小、薄膜厚度以及空气层厚度有关。在入射角小于但接近棱镜与薄膜界面的临界角,薄膜厚度和空气层厚度一定时,古斯汉欣位移量共振增强达到波长的数百倍。     

Adsorption phenomena in amphiphilic systems

The wetting behavior of a ternary mixture of oil, water, and amphiphile in the presence of a surface is studied. An interface model carefully derived from an underlying Ginzburg-Landau theory is introduced, which contains position dependent rigidity and stiffness coefficients. Using this model we predict a rich surface phase diagram containing thin-thick, first-order, and continuous wetting transitions. Application of the model to other interface behavior in these mixtures is also addressed.     

光波在左右手系材料界面处的传输特性

根据电磁场理论推导了左、右手系材料界面处菲涅耳公式及菲涅耳系数的角度表达形式,研究了界面处反射系数和透射系数的变化情况,以及布鲁斯特角的确定和全反射时的光学特性,作为进一步研究左手系的特性和相关光学薄膜器件设计的理论基础.