Although
surfactant micelles usually exhibit superlow friction
at the nanoscale due to the formation of the hydration layer, the
load-bearing capacity (LBC) is limited. In this study, the friction
behaviors of two different surfactant micelles (fluorinated and hydrocarbon
surfactants, denoted as F-surfactant and H-surfactant) were compared,
with the results showing that both can achieve superlow friction (μ
= 0.001–0.002) when the self-assembled micelle layers on the
two surfaces were not ruptured. Although the two different surfactant
micelles have the similar friction behaviors, the LBC of superlow
friction for the F-surfactant is 2.5 times larger than that for the
H-surfactant. The mechanisms of the superlow friction and the reasons
for different LBC were investigated using an atomic force microscopy.
The superlow friction can be attributed to the formation of hydration
layer on the surfactant headgroups, whereas the higher LBC for F-surfactant
originates from the fatness of its carbon chain, which produces the
larger hydrophobic attraction and meanwhile increases the stiffness
of the micelle layer
