LB膜的物理性能与应用

ＬＢ膜是一种分子有序排列的有机超薄膜，这种膜不仅是薄膜科学研究的重要内容，也是物理学，电子学，生物学等多种学科相互交叉渗透的新的研究领域，为近年来国内外研究的热点之一，本文对ＬＢ膜的发展历史，基本要领组装制备，物理特性及栽些应用作了全面扼要的介绍。     

聚酰亚胺LB膜上液晶表面锚定的研究

通过测试光延迟研究了聚酰亚胺ＬＢ膜的光学各向异性，分析了在ＬＢ膜成膜过程中成膜分子的流动取向特性，并研究了液晶的表面锚定能，分析了ＬＢ膜上液晶的取向机制．聚酰亚胺ＬＢ膜的链段的取向程度较强摩擦情形的聚酰亚胺表面的链段取向要差．强摩擦的聚酰亚胺会比聚酰亚胺ＬＢ膜具有更好的排列液晶分子的能力．ＬＢ膜的流动取向模式使得聚酰亚胺成膜分子沿拉伸方向形成一定的有序排列，并诱导液晶分子定向排列，液晶和聚合物分子相互作用是液晶表面排列的主要动力 关键词：     

不同表压下芪盐LB膜二阶光学非线性的研究

研究了芪盐在不同表压下制备的ＬＢ膜的二阶光学非线性。测量得到在低表压增强的二次谐波信号。对比芪盐的π－Ａ曲线和透射光谱，认为在ＬＢ膜中芪盐以固相态存在，低表压时的固相态聚集体的吸收峰３５１ｎｍ使四阶非线性极化率Ｘ＾（４）（－２ω：ω，ω，ω，－ω）产生共振强，四阶光学非线性现象对二次谐波信号产生影响。     

用ATR方法研究LB单分子膜层的等温热脱附过程

对由有机长链花生酸分子所组成的Langmuir-Blodgett单分子膜层(LB膜)的多层结构,利用衰减全反射方法进行了等温热脱附研究,提出了一个物理模型以描述LB膜的脱附过程,得到了LB膜中花生酸分子的不同吸附端的层间脱附能,疏水端为19kcal/mol;亲水端为27kcal/mol.     

LB膜的变入射角透射光学二次谐波产生研究

给出了不同基频光和倍频光偏振态组合情况下，淀积在固体基板上的Ｌａｎｇｍｕｉｒ－Ｂｌｏｄｇｅｔｔ单分子层膜在面对入射光方向和背对入射光方向时，反射及透射光学二次谐波产生随入射角变化关系的理论公式。在此基础上，对一种芪盐ＬＢ膜样品进行变入射角的透射二次谐波产生研究。     

低温等离子体对多孔聚丙烯膜表面改性的研究

红外光声光谱（ＩＲ）分析和光电子能谱（ＥＳＣＡ）分析表明，双向拉伸我孔聚内烯膜（ＰＰ）经等离子体表面改性后，表面产生了多种极性基团，从而增中了表面的亲水性，改性后的ＰＰ膜与胶原复合形成的复合材料表面还出现了离子的型的氨基和羧基等，涂覆深度约为５ｎｍ以上，从而为ＰＰ膜用作药物控释系统中的载体作了初步的探索。     

LB膜的各向异性与二次谐波超平方增长

用偏振紫外－可见吸收及旋转样品二次谐波方法研究了半花菁／花生酸Ｙ型交替ＬＢ多层膜中由垂直浸渍过程诱导和层间相互作用增强的分子在基板平面内的定向排列，提出并证实了随层数增长的平面内附加偶极矩导致光学二次谐波强度随ＬＢ膜厚度的超平方增长关系。     

Thermal annealing effect on the crystallization and optical dispersion of sprayed V2O5 thin films

Polycrystalline vanadium pentoxide (V₂O₅) thin films have been deposited by spray pyrolysis technique on preheated glass substrate. The influence of thermal annealing on the crystallization of V₂O₅ has been investigated. X-ray diffraction analysis (XRD) revealed that the films deposited at T_sub=350 °C were orthorhombic structures with a preferential orientation along 〈0 0 1〉 direction. Moreover, the degree of crystallinity was improved by thermal annealing. Optical properties of these samples were studied by spectrophotometer in the wavelength range 300-2500 nm. Some of the important optical absorptions such as optical dispersion energies E_o and E_d, dielectric constant ε, ratio between number of charge carriers and effective mass N/m^*, wavelength of single oscillator λ₀, plasma frequency ω_p, single resonant frequency ω₀ and the average of oscillator strength S_o, have been evaluated. In the annealing process, the dielectric properties have weak dependencies of film thickness and annealing time. Furthermore, a value of carrier concentration was obtained of 3.02×10²⁵ m⁻³ for the as-deposited film and slight changes with annealing time.     

Role of various LB parameters on the optical characteristics of mixed Langmuir-Blodgett films

This communication reports the spectroscopic characterizations of mixed Langmuir-Blodgett (LB) films of non-amphiphilic N,N-bis (2,5-di-tert-butylphenyl)- 3,4,9-perylenedicarboximide (DBPI) molecules, mixed with polymethyl methacrylate (PMMA) and stearic acid (SA). J- aggregates of DBPI molecules in the mixed LB films have been confirmed by UV-Vis absorption spectroscopic study. Formation of organized structure of molecular stacking in the mixed LB films gives rise to the strong excimeric emission, which is manifested by a broad structureless band in the longer wavelength region of the fluorescence spectra and is confirmed by excitation spectroscopic study. A weak hump at around 576 nm due to monomeric emission is observed in the fluorescence spectra of 0.1 M of DBPI-PMMA mixed LB films of lower number of layers. The intensity of the 0-0 band at 530 nm in the fluorescence spectra is observed to be a function of the molefraction, number of layers, surface pressure of lifting and the matrix materials.     

金膜组分的ICP-AES法分析

研究了在室温下用王水溶解金膜,ＩＣＰ－ＡＥＳ法测定金膜组分银,铜,铁,铅,锑,铋等的方法,该方法简便,实测样品获得了满意结果。     

Structure and photoluminescence of VAC-functionalized ZnO nanoparticles by plasma polymerization

A plasma polymerization method was used to modify the surfaces of ZnO nanoparticles, and the effects of plasma surface modification on photoluminescence (PL) property of ZnO nanoparticles were studied. High-resolution transmission electron microscopy images revealed that a thin film of vinyl acetate (VAC) polymer layer (∼4 nm) was uniformly deposited on the surfaces of the ZnO nanoparticles. The chemical structure of the polymer layer was identified by Fourier transform infrared (FTIR) experiments. The photoluminescence (PL) intensity of the ZnO nanoparticles was found to be significantly decreased by the deposited plasma films. For the particle of smaller size, the ultrathin film indicated better ultraviolet (UV) shielding ability.     

On the dependence of surface undulation on film thickness

This paper investigates the dependence of surface undulation on a film thickness considerably greater than the critical value of a thin film system. It considers that surface tension and residual stress are the main cause of surface undulation. The study found that there is a critical undulation wavelength that minimizes the free energy of a thin film system, that this critical wavelength depends on the film thickness, and the effect of undulation amplitude is insignificant. The research also found that the surface undulation has a negligible influence on the residual stresses in the thin film system.     

Strong blue excitonic emission from CdS nanocrystallites prepared by LB technique

CdS nanocrystallites formed in ordered fatty acid LB multilayers exhibited strong surface states emission ∼550 nm and weak excitonic emission ∼400 nm. Treatment with aqueous CdCl₂ resulted in the suppression of surface states emission and enhancement of the blue excitonic emission. Subsequent annealing in air at 200°C caused an order of magnitude enhancement of excitonic emission. The growth of nanocrystallites during annealing as seen from the red-shift of excitonic absorption and emission is suppressed by the CdCl₂ treatment. The hindered growth of nanocrystallites, the significant enhancement of excitonic emission from CdS, and the suppression of surface states emission are attributed to surface passivation of CdS nanocrystallites by surface oxide formation.     

MgxZn1-xO薄膜的光致发光性能研究

用溶胶-凝胶旋涂的方法在Si(100)衬底上成功制备了MgxZn1-xO薄膜.通过对样品的X射线衍射花样进行分析,发现制得的样品都有明显的C轴取向.掺入Mg后C轴参数逐渐变小,这表明Mg离子进入了ZnO晶格.随着镁的掺入,其光致发光谱中的紫外发射峰的峰位发生明显蓝移,从3.28eV线性地变化到3.45eV.值得注意的是,掺入镁离子后,薄膜的紫外发光和可见发光的强度都显著高于ZnO.     

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简述了当今倍受关注的等离子体聚合薄膜技术和各种等离子体纳米聚合反应装置,讨论了各种纳米材料如氧化锌(ZnO)、碳纳米管(CNT)、碳纳米纤维(CNF)等离子体表面改性结果。     

Crystallization kinetics in phosphate sodium-based glass studied by DSC technique

In this work, differential scanning calorimetry (DSC) was used to study the mechanism of crystallization of 50P₂O₅-27.8Na₂O-16ZnO-6.2Al₂O₃ glass. DSC measurements were performed on bulk and powdered glasses with different particle size. The curve for bulk glass shows one crystallization peak while powdered glasses presented two distinct crystallization peaks. Based on DSC studies, the activation energies obtained were 336±6 and 213±3 kJ mol⁻¹, associated with first and second crystallization peaks, respectively. Analyzing the DSC parameters as a function of particle size, the Avrami n parameter suggests that the peak at low temperature may be associated with surface crystallization while the peak at high temperature is associated with bulk crystallization.     

Electrical properties of thermally evaporated nickel-dimethylglyoxime thin films

Thin Bis-(dimethylglyoximato)nickel(II) [Ni(DMG)₂] films of amorphous and crystalline structures were prepared by vacuum deposition on Si (P) substrates. The films were characterised by X-ray fluorescence and X-ray diffraction. The constructed Al/Ni(DMG)₂/Si(P) metal-insulator-semiconductor devices were characterised by the measurement of the gate-voltage dependence of their capacitance and ac conductance, from which the surface states density D_it of insulator/semiconductor interface and the density of the fixed charges in the oxide were determined. The ac electrical conduction and dielectric properties of the Ni(DMG)₂-Silicon structure were studied at room temperature. The data of the ac measurements of the annealed films follow the correlated barrier-hopping CBH mode, from which the fundamental absorption bandgap, the minimum hopping distance, and other parameters of the model were determined.