Monolayers and Langmuir-Blodgett Films of a Liquid-Crystalline Polysiloxane with a Schiff Base Mesogenic Unit in the Side Chain
Monolayers and Langmuir-Blodgett Films of a Liquid-Crystalline Polysiloxane with a Schiff Base Mesogenic Unit in the Side Chain
复制标题
侧链具有席夫碱介晶单元的液晶聚硅氧烷的单分子层和 Langmuir-Blodgett 薄膜
DOI：
10.1021/la00010a073
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发表时间：
1995
期刊：
影响因子：
3.9
通讯作者：
Qizhen Zhang
中科院分区：
文献类型：
--
作者：
Xiao Chen;Q. Xue;Kongzhang Yang;Qizhen Zhang
用表面压-面积等温线、滞后曲线、X射线衍射、偏振红外光谱和紫外-可见光谱研究了一种新合成的侧链液晶聚合物（PSLC）及其与花生酸（AA）共混物的LB膜和Langmuir膜。结果表明，AA基体可以提高单分子膜的稳定性，改善侧链在膜中的堆积。在高的表面压力下，混合单分子层经历了从有序的液体冷凝到类固体相的相变，对应于聚集体或微晶的形成。在不同的沉积压力和AA的比例下，在疏水基底上可以得到两种类型的LB膜（Y和X）。红外二向色性的详细分析表明，AA或侧链中的间隔基的全反式烃链的轴对于较大的AA的比例相对于表面法线倾斜较小，并且芳香族席夫碱发色团的轴几乎垂直于基底平面。薄膜中的紫外-可见吸收光谱与溶液中的光谱相比发生了高移，表明发色团之间形成了H聚集体。
Langmuir and Langmuir-Blodgett (LB) films of a newly synthesized side-chain liquid-crystalline polymer (PSLC) and its blend with arachidic acid (AA) have been investigated by means of surface pressure-area isotherms, hysteresis curves, X-ray diffraction, and polarized IR and UV-Vis spectroscopies. The results show that AA matrices can enhance monolayer stability and improve the packing of side chains in the film. At high surface pressure, the mixed monolayer undergoes a phase transition from an ordered liquid condensed to a solidlike phase, corresponding to the formation of aggregates or crystallites. Two types LB films (Y and X) can be obtained on the hydrophobic substrates under the condition of different deposition pressures and AA's proportion. A detailed analysis of the IR dichroism suggests that the axis of the all-trans hydrocarbon chains of AA or spacers in the side chain is less tilted to the surface normal for larger AA's proportion and the axis of the aromatic Schiff base chromophore is nearly perpendicular to the substrate plane. The hypsoshift of UV-Vis absorption in the film compared with the spectrum in solution indicates that H aggregates form between the chromophore.