Lateral Force Microscopy Study of the Frictional Behavior of Self-Assembled Monolayers of Octadecyltrichlorosilane on Silicon/Silicon Dioxide Immersed inn-Alcohols

Langmuir ◽  
2001 ◽  
Vol 17 (3) ◽  
pp. 720-732 ◽  
Author(s):  
Susannah C. Clear ◽  
Paul F. Nealey
Langmuir ◽  
1998 ◽  
Vol 14 (3) ◽  
pp. 660-666 ◽  
Author(s):  
Yuqing Zhou ◽  
Hongyou Fan ◽  
Tommy Fong ◽  
Gabriel P. Lopez

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Yen-Chih Liao ◽  
William Hargrove ◽  
Brandon L. Weeks

The tribological properties of two distinctive alkanethiol SAMs, 16-mercaptohexadecanoic acid (MHA) and 1-octadecanethiol (ODT), on gold substrates in various humidity conditions were examined by lateral force microscopy (LFM). The results suggest that hydrophobic ODT SAM is insensitive to humidity. The difference of lateral force signal is within ±10% regardless of humidity. The lateral force signal of hydrophilic MHA SAMs has a significant decrease in signal in humid environments. The influence of bulk water was also investigated by LFM. By imaging under water, the capillary force is eliminated on ODT SAMs, which leads to a lower lateral force. However, the lateral force image was reversed on MHA SAMs, which suggested that hydrophobic forces dominated in water.


2015 ◽  
Vol 180 ◽  
pp. 191-204 ◽  
Author(s):  
B. R. Shrestha ◽  
A. Bashir ◽  
G. N. Ankah ◽  
M. Valtiner ◽  
F. U. Renner

The structure and chemistry of thiol or selenol self-assembled organic monolayers have been frequently addressed due to the unique opportunities in functionalization of materials. Such organic films can also act as effective inhibition layers to mitigate oxidation or corrosion. Cu–Au alloy substrates covered by self-assembled monolayers show a different dealloying mechanism compared to bare surfaces. The organic surface layer inhibits dealloying of noble metal alloys by a suppression of surface diffusion at lower potentials but at higher applied potentials dealloying proceeds in localized regions due to passivity breakdown. We present an in situ atomic force microscopy study of a patterned thiol layer applied on Cu–Au alloy surfaces and further explore approaches to change the local composition of the surface layers by exchange of molecules. The pattern for the in situ experiment has been applied by micro-contact printing. This allows the study of corrosion protection with its dependence on different molecule densities at different sites. Low-density thiol areas surrounding the high-density patterns are completely protected and initiation of dealloying proceeds only along the areas with the lowest inhibitor concentration. Dealloying patterns are highly influenced and controlled by molecular thiol to selenol exchange and are also affected by introducing structural defects such as scratches or polishing defects.


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