AVS 50th International Symposium
    Surface Science Thursday Sessions
       Session SS+OM-ThA

Paper SS+OM-ThA9
Characterization of Carboxyl Functionalized SAMs and Surface-Attached Interlocking Molecules Using Near-Edge X-ray Absorption Fine Structure

Thursday, November 6, 2003, 4:40 pm, Room 327

Session: Self-Assembled Monolayers
Presenter: T.M. Willey, University of California, Davis and Lawrence Livermore National Lab
Authors: T.M. Willey, University of California, Davis and Lawrence Livermore National Lab
A.L. Vance, Lawrence Livermore National Laboratory
T. van Buuren, Lawrence Livermore National Laboratory
C. Bostedt, Lawrence Livermore National Laboratory
B.R. Hart, Lawrence Livermore National Laboratory
R.W. Meulenberg, Lawrence Livermore National Laboratory
A.J. Nelson, Lawrence Livermore National Laboratory
L.J. Terminello, Lawrence Livermore National Laboratory
C.S. Fadley, Lawrence Berkeley National Laboratory
Correspondent: Click to Email
Self-Assembled Monolayers (SAMs) and other organo-thiol compounds on Au(111) have become increasingly important to achieve surface attachment of complex molecules. In order to produce useful films, one needs to understand the orientation, order, and substrate bonding of the molecules. Carboxyl and amino terminated SAMs are useful in functionalizing surfaces for surface attachment and immobilization of proteins, DNA, viruses, as well as using the charged state of the endgroups in switchable surfaces. We are also using such functionalization in surface attached interlocking molecules to attempt to induce and measure reorientation (switching) within interlocking molecules. However, functionalization often (adversely!) affects the synthesis, order, packing, and formation of these films. With proper synthetic protocol, many of these issues can be overcome. Here, NEXAFS results probe the orientation of molecules while XPS is used to determine the attachment and chemical nature of the films. We present NEXAFS spectra to compare and contrast the ordering and between SAMs from mercaptohexadecanoic acid (HS(CH@sub 2@)@sub 15@COOH) a long-chain molecule with strong chain-chain interactions and thioctic acid (S@sub 2@(CH@sub 2@)@sub 2@CH(CH@sub 2@)@sub 4@COOH) with a large base hindering strong interactions between its short chains. Stark conformational differences occur in these films of the endgroups with deprotonation (COO- vs. COOH.) In addition, we will present initial results on ordering and attachment in amino-terminated alkanethiols on gold, and preliminary results using functional groups in switching interlocking molecules on surfaces.