Molecular orientation in LB films of azobenzene-containing long-chain fatty acids and their barium salts studied by FT-IR transmission and reflection-absorption spectroscopy
Molecular orientation in LB films of azobenzene-containing long-chain fatty acids and their barium salts studied by FT-IR transmission and reflection-absorption spectroscopy
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DOI：
10.1021/la00093a024
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发表时间：
1990-03
期刊：
影响因子：
3.9
通讯作者：
T. Kawai;J. Umemura;T. Takenaka
中科院分区：
文献类型：
--
作者：
T. Kawai;J. Umemura;T. Takenaka
用傅里叶变换红外透射光谱和反射吸收光谱定量研究了4种含偶氮苯的长链脂肪酸及其钡盐在LB膜中的分子取向。的尾部和间隔部分的碳链长度，单层的数量，和羧基和羧酸酯基团的分子取向上的头部基团之间的差异的影响进行检查。它的结论是，钡盐是更高的取向相比，相应的酸。这种趋势在具有八个碳尾的钡盐和它们的酸之间是显著的。这些结果与他们以前通过紫外吸收光谱获得的结果一致。此外，烃链和偶氮苯发色团的取向被发现是几乎独立的单分子层的数量，但在第一个单分子层中的羧酸根基团的对称轴的倾斜角是大于那些在上面的单分子层。
Molecular orientations in Langmuir-Blodgett films of 4 kinds of azobenzene-containing long-chain fatty acids and their barium salts are quantitatively evaluated by Fourier transform infrared transmission and reflection-absorption spectroscopy. The effects of carbon chain length of the tail and spacer portions, the number of monolayers, and the head group difference between the carboxyl and carboxylate groups on the molecular orientation are examined. It is concluded that the barium salts are more highly oriented as compared with the corresponding acids. This tendency is remarkable between barium salts with an eight-carbon tail and their acids. These results are consistent with their previous results obtained by UV absorption spectroscopy. Further, the orientation of the hydrocarbon chain and the azobenzene chromophore is found to be almost independent of the number of monolayers, but the tilt angle of the symmetrical axis of the carboxylate group in the first monolayer is larger than those in the upper monolayers.