Ultrathin liquid lubrication film thicknesses at the molecular scale are measured by a new apparatus developed by the authors. Mica is used as the solid specimen and octamethylcyclotetrasiloxane (OMCTS), cyclohexane and n-hexadecane are used as liquid specimens. From experimental measurements, discretization of the lubrication film thickness is observed when the thickness is less than about 10 times the molecular diameter of the intervening liquid. Analysis of experimental data shows that the discretization of the lubrication film thickness is due to the solvation force. Dynamic measurements show that the solvation force is almost the same as the non-sliding case and is independent of the sliding speed of the solid surface.
BastowS. H.BowdenF. P.Physical properties of surfaces II—Viscous flow of liquid films. The range of action of surface forcesProc. R. Soc., A, 1935, 151, 220.
2.
KamojoK.KusamaH.SasadaT.Flow in narrow passages (1st report)—On the surface zone at liquid solid interfaceJ. Japan Soc. Lubric. Engng, 1969, 14, 287.
3.
HornR. G.IsraelachviliJ. N.Direct measurement of structural forces between two surfaces in a nonpolar liquidJ. Chem. Phys., 1981, 75, 1400.
4.
IsraelachviliJ. N.Measurement of the viscosity of liquids in very thin filmsJ. Colloid Interface Sci., 1986, 110, 263.
5.
Van MegenW.SnookI.Solvent structure and solvation forces between solid bodiesJ. Chem. Soc., Faraday Trans. II, 1979, 75, 1095.
6.
Van AlstenJ.GranickS.Molecular tribometry of ultrathin liquid filmsPhys. Rev. Lett., 1988, 61, 2570.
7.
GeorgesJ. M.MillotS.LoubetJ. L.TonkA.Drainage of thin liquid films between relatively smooth surfacesJ. Chem. Phys., 1993, 98, 7345.
8.
SnookI.van MegenW.Structure of dense liquids at solid interfacesJ. Chem. Phys., 1979, 70, 3099.
9.
TarazonaP.VicenteL.A model for density oscillations in liquids between solid wallsMolecular Phys., 1985, 56, 557.
De BruyneF. A.BogyD. B.Numerical simulation of the lubrication of the head-disk interface using a non-Newtonian fluidTrans. ASME, J. Tribology, 1994, 116, 541.
12.
IkedaY.TagoK.Tribological study on molecularly thin films using non-equilibrium molecular dynamicsJ. Jap. Soc. Tribologists, 1995, 40, 253.
13.
Van AlstenJ.GranickS.Tribology studied using automatically smooth surfacesSTLE Tribology Trans., 1990, 33, 436.
14.
GranickS.Motions and relaxations of confined liquidsScience, 1991, 253, 1374.
15.
GranickS.HuH.-W.Nanorheology of confined polymer melts1. Linear shear response at strongly adsorbing surfaces. Langmuir, 1994, 10, 3857.
16.
GranickS.DemielA. L.CaiL. L.PeanaskyJ.Nanorheology of confined liquids and block copolymersIsrael J. Chem., 1995, 35, 75.
17.
PeacheyJ.Van AlstenJ.GranickS.Design of an apparatus to measure the shear response of ultrathin liquid filmsRev. Sci. Instrums, 1991, 62, 463.
HomolaA. M.The role of interfacial forces and lubrication in thin-film magnetic mediaAdv. Info. Storage System, 1991, 1, 279.
20.
HomolaA. M.IsraelachviliJ. N.GeeM. L.McGuigganP. M.Measurements of and relation between the adhesion and friction of two surfaces separated by molecularly thin liquid filmsTrans. ASME, J. Tribology, 1989, 111, 675.
21.
GeorgesJ. M.MillotS.LoubetJ. L.TonkA.MazuyerD.Surface roughness and squeezed films at molecular level.Proceedings of Thirteenth Leeds-Lyon Symposium on Tribology, 1993, p. 443.
22.
GeorgesJ. M.TonkA.MazuyerD.Static and dynamic frictions of compressed polymer layers. Synopses of International Tribology Conference ′95, Yokohama, 1995, p. 1.
23.
LuoJ. B.WenS. Z.CaoN. J.Study of the characteristics of lubricant film at nanometer scale. Synopses of International Tribology Conference ′95, Yokohama, 1995, p. 2.
24.
JohnstonG. J.WayteR.SpikesH. A.The measurement and study of very thin lubricant films in concentrated contactsSTLE Tribology Trans., 1991, 34, 187.
25.
CameronA.The Principles of Lubrication, 1966 (Longmans).
26.
DalmazG.Film thickness and traction measurements in small elastohydrodynamic elliptical contacts.Proceedings of Fifth Leeds-Lyon Symposium on Tribology, 1978, p. 71.
27.
CooperD.MooreA. J.Application of the ultrathin elastohydrodynamic oil film thickness technique to the study of automative engine oilsWear, 1994, 175, 93.
28.
GuangtengG.SpikesH. A.Behavior of lubricants in the mixed elastohydrodynamic regime. Paper presented at the Twenty-first Leeds-Lyon Symposium on Tribology, 1994.
29.
GuangtengG.SpikesH. A.Boundary film formation by lubricant base fluids. Paper presented at the Fiftieth STLE Annual Meeting, Chicago, 1995, paper 95-NP-7D-2.
30.
SmeethM.SpikesH. A.GunselS. The formation of viscous surface films by polymer solutions: boundary or elastohydrodynamic lubrication? Paper presented at the Fiftieth STLE Annual Meeting, Chicago, 1995, paper 95-NP-7D-3.
31.
SmeethM.SpikesH. A.GunselS.Boundary film formation by viscosity index improvers. Paper presented at the STLE/ASME Tribology Conference, Florida, 1995, paper 95-TC-3C-1.
32.
SpikesH.The thickness and rheology of boundary lubricating films. Synopses of International Tribology Conference ′95, Yokohama, 1995, p. 3.
33.
MatsuokaH.KatoT.Discrete nature of ultrathin lubrication film between mica surfacesTrans. ASME, J. Tribology, 1996, 118, 832.
34.
IsraelachviliJ. N.Intermolecular and Surface Forces, 2nd edition, 1992 (Academic Press).
35.
HamrockB. J.DowsonD.Isothermal elastohydrodynamic lubrication of point contacts. Part 1—theoretical formulationTrans. ASME. J. Lubric. Technol., 1976, 98, 223.
36.
MatsuokaH.KatoT.Adhesion forces between mica surfaces in air and liquids. Synopses of International Tribology Conference ′95, Yokohama, 1995, p. 93.
37.
GainesG. L.JrJ. Phys. Chem., 1957, 61, 1408.
38.
ChristensonH. K.Experimental measurements of solvation forces in nonpolar liquidsJ. Chem. Phys., 1983, 78, 6906.
39.
LifshitzE. M.The theory of molecular attractive forces between solidsSoviet Physics, JETP, 1956, 2, 73.
40.
PrieveD. C.RussellW. B.Simplified prediction of Hamaker constants from Lifshitz theoryJ. Colloid Interface Sci., 1988, 125, 1.
41.
WhiteL. R.On the Deryaguin approximation for the interaction of macrobodiesJ. Colloid Interface Sci., 1983, 95, 286.
42.
IsraelachviliJ. N.The calculation of van der Waals dispersion forces between macroscopic bodiesProc. R. Soc., A, 1972, 331, 39.
43.
OrrF. M.ScrivenL. E.RivasA. P.Pendular rings between solids: Meniscus properties and capillary forceJ. Fluid Mechanics, 1975, 67, 723.
44.
GaoC.TianX.BhushanB.A meniscus model for optimization of texturing and liquid lubrication of magnetic thin film rigid disksSTLE Tribology Trans., 1995, 38, 201.
45.
HamrockB. J.DowsonD.Isothermal elastohydrodynamic lubrication of point contacts. Part II-ellipticity parameter resultsTrans. ASME, J. Lubric. Technol., 1976, 98, 375.
46.
HamrockB. J.DowsonD.Isothermal elastohydrodynamic lubrication of point contacts. Part III fully flooded resultsTrans. ASME, J. Lubric, Technol.1977, 99, 264.
47.
HamrockB. J.DowsonD.Isothermal elastohydrodynamic lubrication of point contacts. Part IV—starvation resultsTrans. ASME, J. Lubric. Technol., 1977, 99, 15.
48.
EvansH. P.SnidleR. W.The isothermal elasto-hydrodynamic lubrication of spheresTrans. ASME, J. Lubric. Technol., 1981, 103, 547.
49.
HamrockB. J.DowsonD.Minimum film thickness in elliptical contacts for different regimes of fluid film lubrication.Proceedings of Fifth Leeds-Lyon Symposium on Tribology, 1978, p. 22.
