Gong Jian-Ru, Wan Li-Jun
Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
J Phys Chem B. 2005 Oct 13;109(40):18733-40. doi: 10.1021/jp052581q.
Two-dimensional assemblies of a series of banana-shaped liquid crystal molecules, 1,3-phenylene bis[4-(4-n-alkylphenyliminomethyl) benzoates] (P-n-PIMB, n = 12, 14, 18), are investigated on a highly oriented pyrolytic graphite (HOPG) surface by using scanning tunneling microscopy (STM) at a submolecular level in an ambient environment. Two types of molecular arrangements are observed in these self-assemblies with different stripe widths that resulted from the organization of the alkyl chains. The polarization of the P-n-PIMB monolayers is exactly compensated by the adjacent lamellae with opposite bent direction. Furthermore, a bilayer structure is found in the assembly of P-18-PIMB molecules. In comparison with a gemini surfactant molecule, 4,4'-di[4-(octadecylmethylamino)styryl]-1,1'-pentamethylenebispyridinium dibromide (OPD), P-n-PIMB molecules appear in more complicated packing arrangements. The results in this paper demonstrate the effects of the molecular structures on the adlayer arrangement and will be helpful in fabricating two-dimensional molecular structures on solid surfaces.
通过在环境条件下的亚分子水平上使用扫描隧道显微镜（STM），在高度取向的热解石墨（HOPG）表面研究了一系列香蕉形液晶分子1,3-亚苯基双[4-(4-正烷基苯基亚氨基甲基)苯甲酸酯]（P-n-PIMB，n = 12、14、18）的二维组装体。在这些自组装体中观察到两种类型的分子排列，其条纹宽度不同，这是由烷基链的排列导致的。P-n-PIMB单层的极化被相邻的具有相反弯曲方向的薄片精确补偿。此外，在P-18-PIMB分子的组装体中发现了双层结构。与双子表面活性剂分子4,4'-二[4-(十八烷基甲基氨基)苯乙烯基]-1,1'-亚戊基双吡啶二溴化物（OPD）相比，P-n-PIMB分子呈现出更复杂的堆积排列。本文的结果证明了分子结构对吸附层排列的影响，将有助于在固体表面制备二维分子结构。
