Self-assembled structure of alkyloxy substituted benzoic acid methyl ester on HOPG: An STM study.

Self-assembled structures of 3,4,5-tris-dodecyloxy benzoic acid methyl ester (E12), 3,4,5-tris-tetradecyloxy-benzoic acid methyl ester (E14) and their mixture (E12/E14) have been studied on HOPG by scanning tunneling microscopy (STM). Dimer-like patterns induced by dipole-dipole interaction are observed in E12 and E14 monolayers. The molecules form close-packed rows and interdigitate with the alkyl chains in adjacent molecules. The structural differences are proposed to be from the different length of substituted alkyl chains. Owing to similar adsorption energy, phase separation is observed in the E12 and E14 mixed adlayer with different domains. [ABSTRACT FROM AUTHOR]