Abstract
The dynamic shear properties of molecularly-thin films of unfunctionalized and end-functionalized (telechelic) Fomblin-Z perfluoropolyalkylether (PFPAE) melts with number-average molecular weight M n≈ 3000−4000 g,mol-1 have been studied at shear rates of 10-2−105 s-1 at normal pressures of 1 and 3 MPa. The shear responses are compared to measurements on end-functionalized polymers of the same chemical composition but lower molecular weight, M n≈ 2000 g,mol-1. The predominantly elastic response and high shear moduli of the confined film of unfunctionalized polymer, Fomblin Z03, suggest that it forms a structure likely to solidify already at low pressure. Its lubricating properties are less favorable than the ones found for hydroxyl- (DOL) and piperonyl-terminated Fomblin-Z (AM2001, AM3001), where associated molecules form a structure less prone to solidification under confinement. The thickness of the compressed films of the end-functionalized polymers increased more strongly with molecular weight than as M 0.5n . The shear moduli were found to be larger, the higher the molecular weight, indicating slower relaxations. At a normal pressure of 3 MPa, these films solidified and displayed stick–slip as seen already at 1 MPa in the Z03 film. The limiting shear stress of the unfunctionalized Z03, σ > 3 MPa, exceeded by an order of magnitude the limiting shear stress of all of the end-functionalized polymers. The limiting shear stress of the hydroxyl-terminated polymer was larger than that of the piperonyl-terminated polymer.
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L. Gschwender, C.E. Snyder, Jr., M. Oleksiuk and M. Koehler, Tribol. Trans. 39 (1996) 368.
B. Çavdar, Wear 206 (1997) 15.
A.M. Homola, C.M. Mate and G.B. Street, MRS Bulletin 15 (1990) 45.
C.M. Mate, Phys. Rev. Lett. 68 (1992) 3323.
J. Rühe, G. Blackman, V.J. Novotny, T. Clarke, G.B. Street and S. Kuan, J. Appl. Polym. Sci. 53 (1994) 825.
J. Rühe, V. Novotny, T. Clarke and G.B. Street, J. Tribol. 118 (1996) 663.
V.N. Koinkar and B. Bhushan, J. Appl. Phys. 79 (1996) 8071; J. Vac. Sci. Technol. A 14 (1996) 2378.
B. Bhushan and Z. Zhao, IEEE Trans. Magn. 33 (1997) 918.
S.S. Perry, C.M. Mate, R.L. White and G.A. Somorjai, IEEE Trans. Magn. 32 (1996) 115.
H. Kondo, Y. Hisamichi and T. Kamei, J. Magn. Magn. Mater. 155 (1996) 332.
J. Gui, D. Kuo, B. Marchon and G.C. Rauch, IEEE Trans. Magn. 33 (1997) 932.
C.-B. Xu, C.W. Frank, W.T. Tang and C. Terrill, J. Adhes. 67 (1998) 195.
M.F. Toney and C. Thompson, J. Chem. Phys. 92 (1990) 3781.
C. Gao and P. Dai, IEEE Trans. Magn. 33 (1997) 3118.
Q. Dai, G. Vurens, M. Luna and M. Salmeron, Langmuir 13 (1997) 4401.
B.G. Min, J.W. Choi, H.R. Brown, D.Y. Yoon, T.M. O'Connor and M.S. Jhon, Tribol. Lett. 1 (1995) 225.
T.M. O'Connor, Y.R. Back, M.S. Jhon, B.G. Min, D.Y. Yoon and T.E. Karis, J. Appl. Phys. 79 (1996) 5788.
K.V. Viswanathan, J. Appl. Phys. 75 (1994) 6161.
C. Gao, Y.C. Lee, J. Chao and M. Russak, IEEE Trans. Magn. 31 (1995) 2982.
A.J. Gellman, Curr. Opin. Colloid Interface Sci. 3 (1998) 368.
K. Paserba, N. Shukla, A.J. Gellman, J. Gui and B. Marchon, Langmuir 15 (1999) 1709.
P.H. Kasai,J. Appl. Polym. Sci. 57 (1995) 797.
X. Ma, J. Gui, L. Smoliar, K. Grannen, B. Marchon, M.S. Jhon and C.L. Bauer, Phys. Rev. E 59 (1999) 722; J. Chem. Phys. 110 (1999) 3129.
X. Ma, J. Gui, K.J. Grannen, L.A. Smoliar, B. Marchon, M.S. Jhon and C.L. Bauer, Tribol. Lett. 6 (1999) 9.
C.D. Hahm and B. Bhushan, J. Appl. Phys. 81 (1997) 5384.
F. Danusso, M. Levi, G. Gianotti and S. Turri, Eur. Polym. J. 30 (1994) 1449.
G. Tieghi, M. Levi and R. Imperial, Polymer 39 (1998) 1015.
M. Ruths and S. Granick, J. Phys. Chem. B 103 (1999) 8711.
A. Sanguineti, P.A. Guarda, G. Marchionni and G. Ajroldi, Polymer 36 (1995) 3697.
J.N. Israelachvili and G.E. Adams, J. Chem. Soc., Faraday Trans. I 74 (1978) 975.
J. Van Alsten and S. Granick, Phys. Rev. Lett. 61 (1988) 2570.
J. Peachey, J. Van Alsten and S. Granick, Rev. Sci. Instrum. 62 (1991) 463.
S. Granick and H.-W. Hu, Langmuir 10 (1994) 3857.
J.N. Israelachvili, J. Colloid Interface Sci. 44 (1973) 259.
R.G. Horn, S.J. Hirz, G. Hadziioannou, C.W. Frank and J.M. Catala, J. Chem. Phys. 90 (1989) 6767.
J. Peanasky, L.L. Cai, S. Granick and C.R. Kessel, Langmuir 10 (1994) 3874.
S. Granick, H.-W. Hu and G.A. Carson, Langmuir 10 (1994) 3867.
G. Luengo, F.-J. Schmitt, R. Hill and J.N. Israelachvili, Macromolecules 30 (1997) 2482.
A.M. Homola, H.V. Nguyen and G. Hadziioannou, J. Chem. Phys. 94 (1991) 2346.
S.J. Hirz, A.M. Homola, G. Hadziioannou and C.W. Frank, Langmuir 8 (1992) 328.
Y.-K. Cho and S. Granick, Wear 200 (1996) 346.
P.-G. de Gennes, C. R. Acad. Sci., Ser. II (Paris) 305 (1987) 1181.
J.N. Israelachvili, Intermolecular and Surface Forces, 2nd Ed. (Academic Press, London, 1991).
G. Marchionni, G. Ajroldi and G. Pezzin, Rheology and Tribology of Engine Oils (Society of Automotive Engineers, Warrendale, PA, 1992) pp. 87–96.
Y.-K. Cho, University of Illinois, unpublished results.
G.W. Tyndall, P.B. Leezenberg, R.J. Waltman and J. Castenada, Tribol. Lett. 4 (1998) 103.
R.J. Waltman, D.J. Pocker and G.W. Tyndall, Tribol. Lett. 4 (1998) 267.
R.G. Horn and J.N. Israelachvili, Macromolecules 21 (1988) 2836.
C.M. Mate and V.J. Novotny, J. Chem. Phys. 94 (1991) 8420.
M. Ruths and S. Granick, J. Phys. Chem. B 102 (1998) 6056.
S.T. Milner and T.A. Witten, Macromolecules 25 (1992) 5495.
T.E. Karis and M.S. Jhon, Tribol. Lett. 5 (1998) 283.
A. Subbotin, A. Semenov, E. Mainas, G. Hadziioannou and G. ten Brinke, Macromolecules 28 (1995) 1511.
A. Subbotin, A. Semenov, G. Hadziioannou and G. ten Brinke, Macromolecules 29 (1996) 1296.
A. Subbotin, A. Semenov, G. Hadziioannou and G. ten Brinke, Macromolecules 28 (1995) 3901.
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Ruths, M., Granick, S. Tribology of confined Fomblin-Z perfluoropolyalkylethers: molecular weight dependence and comparison between unfunctionalized and telechelic chains. Tribology Letters 7, 161–172 (1999). https://doi.org/10.1023/A:1019137824102
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DOI: https://doi.org/10.1023/A:1019137824102