Self-assembling of 2,3-phenyl/thienyl-substituted acrylic acids over polycrystalline gold

Self-assembling layers were formed from sulfur-containing cinnamic acid analogues over polycrystalline Au surface. The horizontal organising forces were strong O-H center dot center dot center dot O and weaker C-H center dot center dot center dot S hydrogen bonds (the former interaction kept together the acid dimers serving as the fundamental unit, while the latter was crucial in the construction of the 2D layers), while the vertical organisation forces were provided by Au-S covalent bonds. Measurements by atomic force, scanning electron, infrared and Raman microscopies attested that the dimers were situated in a nearly perpendicular fashion to the Au surface providing a similar to 30-40 nm thick organic "carpet" and out of this layer occasionally, peaks with height of similar to 100-120 nm grew out. The outgrowth of these surface structures were most probably governed by the defects of the polycrystalline metal surface. (C) 2012 Elsevier B.V. All rights reserved.