Abstract
In order to reveal the formation process of a self-assembled monolayer (SAM) of poly-alkylthiophene, a poly-dodecylthiophene film on a gold substrate was analyzed by Fourier-transform infrared spectroscopy. We found that poly-dodecylthiophene successfully formed a SAM on the gold (111) surface. There are two stages for the SAM formation. In the first stage, dodecylthiophene adsorbs continuously on the substrate with the perpendicular orientation until the full coverage is attained. In the second stage, however, the alkyl-chain moiety aligns up to the parallel direction to the substrate surface. Our results indicate that the intramolecular tilt plays a crucial role for the orientation of the thiophene moiety, whereas the intermolecular interaction for the cooperative alkyl-chain alignment.
