Direct Visualization of an Aniline Admolecule and Its Electropolymerization on Au(111) with in Situ Scanning Tunneling Microscope

In situ scanning tunneling microscopy has been used to examine the structure of the aniline adlayer and the conformation of polyaniline molecules produced electrochemically on a Au(111) electrode in 0.1 M sulfuric acid containing 30 mM aniline. As evidenced by the high-resolution STM imaging, a simple method of potential step triggered electropolymerization of aniline molecules. This reaction propagated preferentially in the 〈121〉 directions to produce mostly linear polyaniline molecules. Molecular resolution STM yielded the internal structure of polyaniline molecules.