TY - JOUR
T1 - Controlling gold atom penetration through alkanethiolate self-assembled monolayers on Au{111} by adjusting terminal group intermolecular interactions
AU - Zhu, Zihua
AU - Daniel, Thomas A.
AU - Maitani, Masato
AU - Cabarcos, Orlando M.
AU - Allara, David L.
AU - Winograd, Nicholas
PY - 2006/10/25
Y1 - 2006/10/25
N2 - The penetration behavior of thermally evaporated Au on S(CH 2)15CH3, S(CH2)15CO 2CH3, S(CH2)15-CO2H, K-modified S(CH2)15CO2CH3, and K-modified S(CH2)15CO2H self-assembled monolayers (SAM) on Au substrates is investigated. Gold is a particularly interesting metal since vapor-deposited Au atoms are known to pass through alkanethiolate SAMs on Au{111} substrates at room temperature. Here we show that it is possible to control Au penetration by adjusting the interactions between terminal groups. It is found that Au atoms evenly penetrate into the CH 3 and CO2CH3 films, forming smooth buried layers below the organic thin films. For the CO2H film, although Au atoms can still penetrate through it, filaments and mushroomlike clusters form due to H-bonding between film molecules. In the case of the K-modified CO 2-CH3 or CO2H films, however, most Au atoms form islands at the vacuum interface. These results suggest that van der Waals forces and H-bonds are not strong enough to block Au from going through but that ionic interactions are able to block Au penetration. The measurements were performed primarily using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and atomic force microscopy (AFM). The combination of these highly complementary probes provides a very useful strategy for the study of metal atom behavior on SAMs.
AB - The penetration behavior of thermally evaporated Au on S(CH 2)15CH3, S(CH2)15CO 2CH3, S(CH2)15-CO2H, K-modified S(CH2)15CO2CH3, and K-modified S(CH2)15CO2H self-assembled monolayers (SAM) on Au substrates is investigated. Gold is a particularly interesting metal since vapor-deposited Au atoms are known to pass through alkanethiolate SAMs on Au{111} substrates at room temperature. Here we show that it is possible to control Au penetration by adjusting the interactions between terminal groups. It is found that Au atoms evenly penetrate into the CH 3 and CO2CH3 films, forming smooth buried layers below the organic thin films. For the CO2H film, although Au atoms can still penetrate through it, filaments and mushroomlike clusters form due to H-bonding between film molecules. In the case of the K-modified CO 2-CH3 or CO2H films, however, most Au atoms form islands at the vacuum interface. These results suggest that van der Waals forces and H-bonds are not strong enough to block Au from going through but that ionic interactions are able to block Au penetration. The measurements were performed primarily using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and atomic force microscopy (AFM). The combination of these highly complementary probes provides a very useful strategy for the study of metal atom behavior on SAMs.
UR - http://www.scopus.com/inward/record.url?scp=33750366570&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33750366570&partnerID=8YFLogxK
U2 - 10.1021/ja060084x
DO - 10.1021/ja060084x
M3 - Article
C2 - 17044698
AN - SCOPUS:33750366570
VL - 128
SP - 13710
EP - 13719
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 42
ER -