Fundamental mechanisms of interfacial friction. 2. Stick-slip friction of spherical and chain molecules

Journal Article · Thu Oct 28 04:00:00 EDT 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100145a031· OSTI ID:5424103

Yoshizawa, Hisae; Israelachvili, J ^[1]

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1. Univ. of California, Santa Barbara, Ca (United States)

The friction and rheological properties of molecularly thin films of hexadecane between two shearing mica surfaces were measured under different conditions of load or applied pressure, film thickness, sliding velocity, temperature, and time or previous history. The aim was to investigate the tribological and rheological properties of ultrathin liquid films composed of chain molecules and to compare these properties with those of spherical molecules. The differences were found to be more quantitative than qualitative, and the results therefore provide insights into the general properties of liquids in thin films. The results show that during steady-state sliding between two solid crystalline surfaces, a liquid film may be considered to be in a one-phase or two-phase dynamic regime. In the two-phase regime, the film undergoes periodic [open quotes]stick-slip[close quotes] transitions between a solidlike and a liquidlike state. However, especially in the case of chain molecules such as hexadecane, the liquidlike state is very different from the bulk liquid. The frequency of transitions between the two dynamic states determines the static and dynamic friction forces and other dynamic properties of a shearing film. The effects produced by changing the load, temperature, sliding velocity, stopping time, etc., were found to be highly correlated. 49 refs., 21 figs., 3 tabs.

• OSTI ID: 5424103
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 97:43; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
661300 -- Other Aspects of Physical Science-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALKANES
DATA
EXPERIMENTAL DATA
FILMS
FLUIDS
FRICTION
HEXADECANE
HYDROCARBONS
INFORMATION
INTERFACES
LIQUIDS
MICA
MINERALS
NUMERICAL DATA
ORGANIC COMPOUNDS
RHEOLOGY
SILICATE MINERALS
SLIP
SURFACE PROPERTIES
THIN FILMS
TRIBOLOGY