LB薄膜技术在尖端材料制备中的应用

LB(Langmuir-Blodgett)薄膜技术可以在分子水平上进行材料设计,是实现分子工程的重要手段.LB膜可以方便地沉积纳米级的功能微粒和薄膜,也是制备梯度功能材料的方法之一.简要综述了LB薄膜技术在功能晶体、纳米半导体及铁电体等尖端材料制备中的应用,并展望了其相关应用研究的重要前景.     

基于LBM的波浪作用下动量射流数值模拟

为了进一步研究射流在有限水深波浪环境下的流动规律,拓宽LBM在水利工程学科中的应用范围,将LB方法的原理应用于自由表面处理、边界条件设定、紊流模型的耦合求解、造波及消波等关键问题上,建立了二维多松弛LB数值波浪水槽模型。运用该模型模拟不同波浪环境下动量射流的紊动特征及变化规律,得到射流在不同工况下的轴线速度衰减、扩展半宽变化和横断面速度分布等规律。研究表明,该模型具有很好的适用性,可以较好地模拟射流问题。     

硬脂酸修饰Lipolase脂肪酶的性能

采用N-羟基琥珀酰亚胺活化法用硬脂酸对Lipolase脂肪酶进行了化学修饰。研究了Lipolase脂肪酶的水解活力和酯化活力,重点研究了界面催化活性和表/界面张力。实验结果表明:与未修饰酶相比,修饰Lipolase的水解活力略有下降,但正己烷中的酯化活力和界面水解活力均明显提高;修饰Lipolase降低表面张力与界面张力的能力提高。用LB技术制备Lipolase的单分子层膜,发现修饰Lipolase的∏-A曲线上移,表明修饰Lipolase更易在表面形成单分子层膜。可见Lipolase脂肪酶经硬脂酸修饰后界面活性提高、有利于在有机相或两相界面催化化学反应。     

Electrochemistry at capped platinum nanoparticle Langmuir Blodgett films: A study of the influence of platinum amount and of number of LB layers

Platinum nanoparticles (n-Pt), over-grafted with 2-thiophenecarbonyl chloride are assembled on gold electrodes, by the Langmuir Blodgett (LB) technique using behenic acid (BHA) as promoting agent. These layers are electrochemically active without any preliminary activation. The [Fe(CN)₆]^3−/4− redox couple was used as electrochemical probe. This paper reports on the influence of the number of deposited LB layers, and the n-Pt density on the electrochemical response. n-Pt density was modified by the change of the “BHA/n-Pt” ratio. Cyclic voltammograms of “[Fe(CN)₆]^3−/4−” were observed whatever the coating conditions. As soon as the first layer was deposited the electrochemical response was associated to the n-Pt coverage, its response slightly increased up to a steady state for five or seven layers. As expected, the increase of the Pt density favored the increase of the current density. XPS analysis performed before and after electrochemical cycling showed that 4-mercaptoaniline capped platinum nanoparticles, and their over grafting were chemically and electrochemically stable. Analysis of influence of the number or the n-Pt density of the layers showed that the electrochemically active part of LB electrodes was provided by the last layer plus a part of the underlying one.     

卟啉与铜Cu（II）卟啉配合物LB膜的制备及性质研究

合成了5-（间羟基苯基）-10,15,20-三对氯苯基卟啉（5-（m-hydroxyphenyl）-10,15,20—tir（P—chlorohenyl）porphyrin,m-OH—TCP）及铜卟啉配合物（m-0H—TCP—Cu（Ⅱ））,并系统地研究了其在气／液界面上的成膜性能。利用UV--vis分光光度计,原子力显微镜等方法对其膜的表面形貌及金属离子Cu（Ⅱ）对卟啉环在LB膜中的排列取向及相互作用的影响进行了详细研究。实验结果表明：在制备的单层膜中,当亚相为超纯水时,m-OH—TCP分子中卟啉环面与水平面倾角约为14．5°;当改变亚相环境时（亚相为Cu（Ⅱ）离子浓度为5×10^ -4 mol／L的水溶液）,m-OH—TCP分子中卟啉环面与水平面倾角约为51．9°;而对于合成的铜卟啉配合物（亚相条件为超纯水）,m-OH—TCP～Cu（Ⅱ）分子中卟啉环面与水平面倾角约为33．2°;证明在亚相中引入Cu（Ⅱ）,可以有效的诱导卟啉环取向,亚相中Cu（Ⅱ）的诱导机理可能是通过Cu（Ⅱ）与卟啉环面空腔形成的氢键作用,而非配位作用。这为卟啉衍生物功能纳米材料性质LB膜研究提供了理论和实验依据。     

智能高分子膜材

本文介绍了智能高分子膜的概念。结合分离膜和ＬＢ膜实例，探讨了智能高分子膜的特性及其潜在应用前景。     

LB技术制备的ZrO2纳米薄膜摩擦学行为

在单晶硅表面制得花生酸锆hngmuir—Blodgett薄膜,对该薄膜在500℃条件下热处理30min,得到致密ZrO2薄膜。利用AFM,XPS,SEM对其结构和形貌进行表征,摩擦磨损试验结果表明,利用该方法制备的ZrO2薄膜表现出良好的减摩抗磨性能。     

酞菁铜衍生物LB膜／N－Si光伏电池的反常二极管整流效应

从表面态和材料电阻率的角度分析了酞菁铜衍生物ＬＢ膜光伏电池的反常整流效应，讨论了该效应与光生电流的关系，并介绍了消除反常现象提高光生电流的实验方法。     

焊接热输入对近焊缝区组织性能的影响

采用焊接热模拟技术模拟不同焊接热输入条件下,峰值温度为1 350℃时对应近焊缝区的组织和性能,并对母材进行宏观力学特性测试;对比分析不同焊接热输入条件下所得近焊缝区的组织和性能。结果表明:经过3种不同焊接热输入所得近焊缝区的组织均由板条状贝氏体和少量碳化物组成;随着焊接热输入的增加,近焊缝区组织晶粒变大,贝氏体板条束变粗变厚,析出的碳化物数量增多,并且强度降低、韧性增强,但总体上跟母材的性能基本一致;当焊接线能量为12 kJ/cm时近焊缝区达到最佳的强韧性匹配。     

Optically synaptic films using spiropyran J-aggregates

Spiropyran SP1822 J-aggregate LB films show a non-linear photochromic response with a threshold against the incident light intensity of a CW dye laser. Using two laser beams operating below the threshold level intensity, the logic ‘AND’ function was found to be optically stored as an overlapping region of two incident patterns. We proposed the adoption of an LB film of spiropyran J-aggregates to store the memory matrix T_ijkl as an overlapping region of learning input pattern V_ij and multi-image input pattern V_kl in order to construct an optical neural network system based on Hopfield model.