Tailoring Alkane Uniaxial Self-Assembly via Polymer Modified Step Edges

Controlling the orientations of molecules in self-assembled monolayers on surfaces is an effective means to construct high quality organic devices. Herein, we utilize linear polymer-modified step edges as a simple and peculiar template for regulating the subsequent self-assembly of alkane molecules (n-C32H66). With this strategy, all the alkane molecules orientate along the step edge ([011] directions). Combining with systematical DFT calculations, we demonstrated that it is the van der Waals interactions between the molecules that leads to: (1) the initially adsorbed alkane monomers lie parallel to the polymers; (2) the adjacent alkane molecules show a parallel configuration. Since the polymers anchor on the surface along an exclusive [011] direction, all the adsorbed molecules in the self-assembly islands are regulated along the [011] directions as well.