Achieving both Nanopatterning and Desired Upright Orientation with Alkanedithiol Self-assembled Monolayers on Gold

Jing-Jiang Yu PhD
Nanotech 2008

Organodithiols on noble metals such as gold are good candidates to generate thiol-terminated self-assembled monolayers (SAMs) if molecules can form a close-packed and standing-up layer on the substrate as the case of alkanethiols. However, dithiols usually yield lying-down or looped alkanedithiolates on gold via the binding of both SH groups when adsorbed layers are prepared from widely used natural growth approaches. Here, a new approach to circumvent that obstacle and achieve high-quality thiol-terminated assemblies is developed. It involves an atomic force microscopy (AFM)-based lithography method known as nanografting performed in a dithiol solution. Using α, w-aliphatic dithiols as an example, dithiol SAMs prepared by both natural growth and nanografting are well characterized by AFM. High-resolution imaging and height measurements clearly demonstrate that dithiol molecules are densely packed and adopt a standing-up conformation in the fabricated patterns of dithiol SAMs to present free SH groups on the surface. In addition, nanografting enables the fabrication of thiol-terminated layers on gold with nanometer-scale precision in geometry, size and location. These designed thiol-terminated nanostructures can be served as surface templates to direct the metal deposition.

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Related Application Notes

New Approach to Generate Thiol-terminated SAMS on Gold

Manipulation of Gold Particles