Materials Research Bulletin, Vol.34, No.3, 447-453, 1999
Wettability and friction of CF3-terminated monolayer films on gold
Studies of the wettability and friction of self-assembled monolayers (SAMs) generated from the terminally fluorinated alkanethiols (CF3(CH2)(n)SH, n = 9-15) on gold are reported. These data were compared to those of SAMs generated from the non-fluorinated analogs (CH3(CH2)(n)SH, n = 9-15). The CF3-terminated SAMs were less wettable by hexadecane and methylene iodide, but surprisingly more wettable by water and glycerol than were the CH3-terminated SAMs. Measurements of friction by atomic force microscopy (AFM) revealed an approximate threefold increase in friction on the CF3-terminated films compared to the CH3-terminated films. A new model for the frictional response of fluorinated SAMs is proposed.
Keywords:SCANNING-TUNNELING-MICROSCOPY;SELF-ASSEMBLED MONOLAYERS;ATOMIC-FORCE MICROSCOPY;MOLECULAR-DYNAMICS