ANYL 182 |
| For natural self-assembly, alkanedithiols assemble in a lying-down orientation because both SH groups bind to gold through chemisorption. Using á,â-aliphatic dithiols as a model, alkanedithiol self-assembled monolayers (SAMs) prepared by both natural growth and nanografting were characterized in situ with atomic force microscopy (AFM). Nanografting is an AFM-based lithography which enables fabrication of SAMs with nanometer-scale precision for geometry, size and location. High-resolution AFM images and height measurements clearly demonstrate that dithiol molecules are densely packed and adopt a standing-up conformation in nanografted patterns of dithiol SAMs to present free SH groups on the surface. Because of spatial confinement, a different self-assembly mechanism takes place when nanografting. Side-by-side comparisons of the thickness of alkanedithiols versus the well-established dimensions of n-alkanethiol SAMs were used to measure the thickness of dithiol SAMs at the nanoscale. Nanografting provides a convenient approach to engineer the presentation of thiol groups at the surface of SAMs. |
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Directed Assemblies Using Surface Templates
1:25 PM-4:45 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 335, Oral
Division of Analytical Chemistry |