Stripe domain analysis of alkanethiol and alkynethiol monolayers self-assembled on the surfaces of gold grains

The self-assembled monolayers (SAMs) of alkanethiols such as 1-dodecanethiol (DDT) on the surface of polycrystalline gold grain on quartz crystal microbalance (QCM) at room temperature and alkynethiols such as phenylethynyl thiol (PET) on the surface of Au(111)/mica under − 65 °C have been fabricated. A multimode scanning probe microscope (SPM) investigation for the first time reveals the formation of stripe domain of DDT SAMs together with roundish domain. This feature was not caused by an annealing treatment but might be induced by coexistence of a few different facets and reconstruction of the surface on the grain. The stripe domain of PET SAMs could also be found on the surface of the grain, which was within the substrate of the gold/mica. It shows that the feature of the stripe domain for organothiol monolayers self-assembled on gold grain surfaces possesses a certain generality. Furthermore, the arrangement of organothiol stripe domain can be well understood from the interpretation of the relationship between the stripe width and width direction, molecule interval distance, molecule length and tilt angles of the thiols.