Stratified Dipole-Arrays Model Accounting for Bulk Properties Specific to Perfluoroalkyl Compounds
Stratified Dipole-Arrays Model Accounting for Bulk Properties Specific to Perfluoroalkyl Compounds
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DOI：
10.1002/cplu.201402156
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发表时间：
2014-10
期刊：
影响因子：
3.4
通讯作者：
T. Hasegawa;T. Shimoaka;Nobutaka Shioya;K. Morita;M. Sonoyama;T. Takagi;T. Kanamori
中科院分区：
文献类型：
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作者：
T. Hasegawa;T. Shimoaka;Nobutaka Shioya;K. Morita;M. Sonoyama;T. Takagi;T. Kanamori
全氟烷基化合物已知在材料表面呈现疏水特性，尽管C - F键有较大的偶极矩，这应该会使分子表面具有极性且亲水。这种不一致性长期以来一直是一个有待解决的化学问题。在此，提出了一种分层偶极阵列模型：通过形成全氟烷基（Rf）基团的二维聚集体，分子极性表面可以完全被隐藏；由于Rf基团的螺旋结构，这种聚集体是由偶极 - 偶极相互作用阵列自发诱导形成的。在该模型中，“短”Rf基团应起到具有亲水特性的单个Rf基团的作用，而“长”Rf基团应自发形成六边形聚集体。为了检验该模型，合成了具有不同Rf长度的含Rf的肉豆蔻酸，并借助精确的红外光谱分析，利用朗缪尔单分子层技术分析了它们的聚集特性。
Perfluoroalkyl compounds are known to exhibit a hydrophobic character on the surface of the material, although the CF bond has a large dipole, which should make the molecular surface polar and hydrophilic. This inconsistency has long been a chemical matter to be solved. Herein, a stratified dipole-arrays model is proposed: the molecular polar surface can be fully hidden by forming a two-dimensional aggregate of perfluoroalkyl (Rf) groups; this aggregate is spontaneously induced by dipole–dipole interaction arrays owing to the helical structure of the Rf group. In this model, a ‘short’ Rf group should play the role of a single Rf group with a hydrophilic character, whereas a ‘long’ Rf group should spontaneously form a hexagonal aggregate. To examine this model, Rf-containing myristic acids with various Rf lengths have been synthesized and their aggregation properties are analyzed by using the Langmuir monolayer technique aided by precise IR spectroscopic analysis.