共查询到17条相似文献,搜索用时 57 毫秒
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利用二(3-叔丁基硅氧基)萘酞菁硅 (SiNc) Langmuir-Blodgett (LB) 膜对丝状液晶的定向进行了研究,发现在不同膜压下沉积的SiNc LB膜具有不同的定向效果.在15mN/m低膜压下沉积的LB膜上丝状液晶主要呈沿膜面水平排列,而30mN/m高膜压下沉积的LB膜则取垂直膜面取向.原子力显微镜(AFM)对相应的LB单层膜和多层膜进行的分子尺度上的形貌研究发现,高膜压条件下SiNc分子以分离的单体或聚集体形式非连续地在基片上呈线性堆积排列,形成一定的分子“纳米线”,并且大环平面垂直于基片
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聚酰亚胺LB膜的研究:Ⅰ聚酰胺酸N,N—二甲基十八胺前聚物的LB膜 总被引:1,自引:0,他引:1
聚酰胺酸N,N-二甲基十八胺是制备本身不具备两亲性的聚酰亚胺LB膜的前聚物。合成制备了均苯四酸二酐-4,4’-二胺基二苯酸N,N-二甲基十八胺,研究了它单分子膜的各异性,比较了伯胺和叔胺膜的不同,并用低角X射线衍射研究这前聚物LB膜分子的详细排列。 相似文献
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本文以LB膜技术研究了向列相液晶的取向机理。选择了四种不同金属的可溶性酞菁化合物MPc-R4作为取向材料,拉制成LB膜,诱导向列相正性液晶E-7。通过对菁酞LB膜的表征和液晶取向及电光性能的研究,认为液晶的取向是由分子间的相互作用力决定的。 相似文献
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本文首次利用LB膜作为分子—金属间的隔离层,考察了表面增强喇曼散射的电磁增强机理,监测了表面增强喇曼散射信号随隔离层厚度的变化。在银膜/LB膜/吡啶+氯化钾系中,实验结果表明,隔离层厚度为5nm时,表面增强喇曼散射效应仍然存在,但在15nm时已测不到其信号,实验支持了电磁增强机理。 相似文献
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本文研究了5,10,15,20-四(对-山嵛酸乙酯-α-氧代苯基)卟啉在气-液界面的成膜性能。在优化实验条件下制备了该化合物的多层LB膜。利用偏振FT-IR谱测定了卟啉上脂链取代基在LB膜结构中的取向。结果表明脂链轴线与载片法线间夹角为27°。 相似文献
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荧光法比吸光度法灵敏,更适用于超薄膜系如LB膜的表征。拉制了荧蒽和苯并[b]荧蒽镶嵌在硬脂酸基质中的LB膜,探讨了它们的稳态和时间分辨荧光性质。实验表明,两种分子以单体形式存在于LB膜中。 相似文献
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The elastic energy density of Iiquid crystal under the action of external electric field E is given by F=F(ni,ni,j,Ei,Ei,j……)where n is the director and ni,j,,Ei,j the gradients. By a systematic expansion of F in polynomials and the use of material symmetries, we obtain macroscopically for nematics and cholesterics all the possible external field-effects. In addition to the well-known dielectric interaction (n · n)and the flexoelec-tric effects of Meyer,-e1(E · n)(∇ · n)-e3 E · (n ∇ ·)n,we find a new term e0n · (n · ∇)E which corresponds to the flexoelectric effect related to electric quadrupoles introduced microscopically by related to electric quadrupoles introduced microscopically by Prost and Marcerou, This new term is not equivalent to the previous two terms of Meyer. An experiment to measure this new flexoelectric constant eo is proposed. Previous experiments measuring fIexoelectric constants are compared and discussed in the light of our theory, which also applies to other cases of external vector fields. 相似文献
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The deposition of silver on an ordered alumina film prepared on Re(0001) surface has been studied by Auger electron spectroscopy (AES), low energy electron diffraction (LEED) and high resolution electron energy loss spectroscopy (HREELS). The results show that Ag grows initially as clusters at 90K and 300K. A red shift of the Ag surface plasmon as a function of decreasing coverage is observed, which is related to the cluster size effect. A surface plasmon characteristic of metallic Ag appears at coverages higher than 2.8 monolayer equivalent. 相似文献