Squeeze-out of branched alkanes on graphite.
We study squalane and heptamethylnonane (HMN) confined between a conducting atomic force microscope tip and a graphite surface. Solvation layering occurs for both liquids but marked differences in the squeeze out mechanics are observed for ordered or disordered monolayers. The squalane monolayer at 25 degrees C is an ordered solid, as verified by direct imaging, and the squeeze out can be modeled using elastic continuum mechanics. HMN is in a disordered state at 25 degrees C and cannot be modeled as a single elastic asperity even in solid-solid contact because HMN liquid is trapped in the contact zone.
Gosvami
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Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576.
Sinha
S K
SK
O'Shea
S J
SJ