Modification of aliphatic self-assembled monolayers by free-radical-dominant plasma: the role of the plasma composition.
Modification of octadecanethiolate self-assembled monolayers on Au by nitrogen-oxygen or argon-oxygen downstream microwave plasma with a low oxygen content (estimated below several percent) has been studied by synchrotron-based high-resolution X-ray photoelectron spectroscopy and water contact angle measurements. For both types of plasma, the primary processes were found to be the loss of conformational and orientational order and the oxidation of the alkyl matrix and headgroup-substrate interface. At the same time, the film modification occurred much faster and with different intermediates for the nitrogen plasma than for the argon plasma. The reasons for these differences are considered in terms of the different reactivities and different efficiencies of the energy transfer between the plasma constituents in these two types of plasma.
Weng
Chih-Chiang
CC
Department of Materials Science and Engineering, National Cheng Kung University, No. 1, University Road, Tainan 70101, Taiwan.
Liao
Jiunn-Der
JD
Wu
Yi-Te
YT
Wang
Ming-Chen
MC
Klauser
Ruth
R
Grunze
Michael
M
Zharnikov
Michael
M