Effect of alkanethiol self-assembled monolayers on the electrochemical polymerization of pyrrole on the gold electrodes

Pyrrole was polymerized on alkanethiol self-assembled SAMs monolayers modified gold electrodes through electrochemical method. The effects of alkyl chain length and the end functional groups of the SAMs on the polymerization of pyrrole were studied by chronoamperometry, cyclic voltammograrns and electrochemical impedance spectroscopy. In the case of SAMs with a high integrity, the polypyrrole grew on the top of SAMs. However, in the case of a large number of pinhole defects, the formation of polymer nuclei on pinhole sites scattered in the SAMs, and then the polymer grew on the entire surface of the SAMs. These results showed that the electrochemical polymerization was easier with shorter alkyl chains, and high hydrophobility of the SAMs could promote the polymer film growth.