Controlling the height of nanopatterns of functionalized n-alkanethiol SAMs written by nanografting: effects of concentration and writing parameters

ANYL 51

Algernon T. Kelley, akell14@lsu.edu, Chemistry Department, Louisiana State University, 232 Choppin Hall, Baton Rouge, LA 70803 and Jayne C. Garno, jgarno@lsu.edu, Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, LA 70803.
Under certain conditions, self-assembled monolayers (SAMs) of carboxylate-terminated n-alkanethiols consistently produce bilayers of molecules for nanopatterns written on Au(111). Strong head-to-head interactions can direct the self-assembly of molecules into bilayers. At low concentration (on the order of 10-100 micromolar) nanopatterns of 16-mercapto hexadecanoic acid exhibit the expected thickness of a monolayer; whereas at higher concentrations, nanografted patterns are observed to form a double layer (below). In contrast, methyl-terminated SAMs uniformly form nanopatterns with heights corresponding to a monolayer, regardless of experimental parameters. Nanografting is accomplished in thiol solutions by scanning an area of a matrix SAM using high force. By repeatedly writing over areas several times, nanopatterns of 16-MHA form a bilayer. Nanopatterns of methyl-terminated alkanethiols exhibit heights corresponding to a monolayer regardless of concentration and writing parameters. Images of nanografted patterns written with designed systematic changes in writing and concentration parameters will illustrate the effects of headgroups on solution-based self-assembly of n-alkanethiols.

 

General Papers
7:00 PM-9:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster

Division of Analytical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006