Self Organization into Bilayer of Fluorocarbon Amphiphiles in Aromatic and Aliphatic Solvent

在本项目中，我们将自组织双分子层形成的概念从水系统扩展到非水系统，并建立了组分两亲体的分子设计。新型两亲性化合物含有两个氟碳链作为疏溶剂单元和柔性油基链作为亲溶剂单元，它们在烃类介质中可以自组织成类似于水介质中的双层结构。电镜显示其形态各异。这些两亲植物通常含有促进分子间吸引的酰胺连接物。红外光谱分析表明，在形成双分子层的氯环己烷中，酰胺键向较短的波数偏移。这种位移在通过差示扫描量热法（DSC）确定的相变温度以上消失。红外光谱数据还表明，碳氟化合物链在15ºC时呈螺旋形，在40ºC时呈锯齿形。这种构象变化与双分子层的形成有关。在空气-氯环己烷界面处观察到单层形成。分子的横截面与碳氟化合物链的横截面一致，表明存在一个浓缩的单层。表面吸附的热力学变化与DSC对分散双分子层的分析结果一致。因此，分散型双分子层的相变必须发生在单体分散体和双分子层之间，而不像水性双分子层。综上所述，非水双分子层的分子设计需要基于长碳氟链，有效的分子间相互作用，如氢键和偶极吸引，以及增强的亲溶剂性。

In this project, we extended the concept of self-organizing bilayer formation from aqueous systems to non-aqueous systems, and established the molecular design of the component amphiphile. Novel amphiphilic compounds which contain two fluorocarbon chains as solvophobic unit and flexible oleyl chain as solvophilic unit underwent self-organization in hydrocarbon meflia to bilayer assemblies similar to those in aqueous media. Electron microscopy displayed their varied morphologies. These amphiphiles commonly contained the amide connector that promoted intermolecular attraction. Infrared spectroscopy showed that the amide bond shifted to a shorter wavenumbers in chlorocyclohexane in which the bilayer was formed. This shift was lost above the phase transition temperature as determined by differentialscanning calorimetry (DSC). The IR data also showed that the fluorocarbon chain assumed a helical conformation at 15ﾟC and a zig-zag conformation at 40ﾟC. This conformational change was associated with the bilayer formation. The monolayer formation was observed at the air-chlorocyplohexane interface. The molecular cross-section agreed with that of the fluorocarbon chain, indicating the presence of a condensed monolayer. The thermodynamic changes of the surface adsorption agreed with those obtained for the dispersed bilayer by DSC. Therefore, the phase transition of the dispersed bilayer must occur between the monomeric dispersion and the bilayer, unlike those of aqueous bilayers. In conclusion, molecular design of non-aqueous bilayers needs to be based on long fluorocarbon chains, effective intermolecular interactions such as hydrogen bonding and dipolar attraction, and enhanced solvophilicity.