An Atomic Force Microscopy Study on Self-assembled Monolayers of Fluorinated Thiols and Disulfides on Polycrystalline Gold: Implications of the Mechanical Stability, Molecular Order, Pull-off Forces and Frictional Properties for Application in Chemic

摘要

Self-assembled monolayers (SAMs) of various classes of organic molecules on solid substrates (especially SAMs of thiols, disulfides and thioethers on gold) have been of widespread interest during the last two decades' SAMs can be regarded as model surfaces for polymers in general. Recently, SAMs have been successfully utilized for tip modifications of scanning force microscopy (SFM) tips. Derivatized tips can be used to quantitatively measure the interaction forces between proteins, or complementary strands of DNA, as well as for "chemically sensitive" SFM. In the latter examples, an enhanced frictional contrast in the lateral force mode, or different adhesion forces have been utilized in order to differentiate areas consisting of chemically different species. Mapping the lateral distribution of functional groups on polymer surfaces with chemically sensitive SFM promises to provide profound insights into unknown mechanisms of polymer surface modifications.