DOI QR코드

DOI QR Code

Superb Mechanical Stability of n-Octadecyltriethoxysilane Monolayer Due to Direct Chemical Bonds between Silane Headgroups and Mica Surface: Part I

  • Kim, Sungsoo (Department of Nano-Polymer Materials Engineering, PaiChai University)
  • Received : 2010.05.24
  • Accepted : 2010.06.24
  • Published : 2010.06.30

Abstract

It is still controversial where the improved stability of n-octadecyltriethoxysilane self-assembled monolayer (OTE SAM) on plasma-pretreated mica surface exactly originates from. To date, it has been well known that the extensive cross-polymerization between silane head-groups is a crucial factor for the outstanding mechanical strength of the monolayer. However, this study clearly showed that the stability comes not only from the cross-links but also, far more importantly, from the direct chemical bonds between silane headgroups and mica surface. To examine this phenomenon, n-octadecyltrichlorosilane monolayers were self-assembled on both untreated and plasma treated mica surfaces, and their adhesion properties at various physical conditions (relative humidity, high stress, and contact repetition) were investigated and compared through the use of the surface forces apparatus technique. It revealed that, in highly humid conditions (>90%RH), there is a substantial difference of stability between untreated and plasma treated cases and the plasma treated surface is mechanically much more stable. It obviously proves that the extensive chemical bonds indeed exist between silane head-groups and plasma treated mica surface and dramatically improve the mechanical stability of the OTE monolayer-coated mica substrate.

Keywords

References

  1. C. R. Kessel and S. Granick, "Formation and characterization of a highly ordered and well-anchored alkylsilane monolayer on mica by self-assembly", Langmuir, Vol. 7, p. 532, 1991. https://doi.org/10.1021/la00051a020
  2. J. Peanasky, H. M. Schneider, S. Granick, and C. R. Kessel, "Self-assembled monolayers on mica for experiments utilizing the surface forces apparatus", Langmuir, Vol. 11, p. 953, 1995. https://doi.org/10.1021/la00003a044
  3. T. Ohtake, N. Mino, and K. Ogawa, "Effect of hydrocarbon chain length on arrangement of chemically adsorbed monolayers", Langmuir, Vol. 8, p. 2081, 1992. https://doi.org/10.1021/la00045a001
  4. T. Vallant, H. Brunner, U. Mayer, H. Hoffmann, T. Leitner, R. Resch, and G. Friedbacher, "Formation of self-assembled octadecylsiloxane monolayers on mica and silicon surfaces studied by atomic force microscopy and infrared spectroscopy", J. Phys. Chem. B, Vol. 102, p. 7190, 1998. https://doi.org/10.1021/jp981282g
  5. D. W. Britt and V. Hlady, "An AFM study of the effects of silanization temperature, hydration, and annealing on the nucleation and aggregation of condensed OTS domains on mica", J. Colloid Interface Sc., Vol. 178, p. 775, 1996. https://doi.org/10.1006/jcis.1996.0177
  6. X. D. Xiao, G. Y. Liu, D. H. Charych, and M. Salmeron, "Preparation, structure, and mechanical stability of alkylsilane monolayers on mica", Langmuir, Vol. 11, p. 1600, 1995. https://doi.org/10.1021/la00005a031
  7. F. Tian, X. D. Xiao, M. M. T. Loy, C. Wang, and C. L. Bai, "Humidity and temperature effect on frictional properties of mica and alkylsilane monolayer self-assembled on mica", Langmuir, Vol. 15, p. 244, 1999. https://doi.org/10.1021/la981008d
  8. J. Campos-Teran, J. Mas-Oliva, and R. Castillo, "Phase transitions of phospholipid monolayers penetrated by apolipoproteins", J. Phys. Chem. B, Vol. 108, p. 20442, 2004. https://doi.org/10.1021/jp048305d
  9. S. Kim, H. K. Christenson, and J. E. Curry, "The effect of humidity on the stability of an octadecyltriethoxysilane monolayer self-assembled on untreated and plasma-treated mica", Langmuir, Vol. 18, p. 2125, 2002. https://doi.org/10.1021/la011020x
  10. S. Kim, H. K. Christenson, and J. E. Curry, "N-octadecyltriethoxysilane monolayer coated surfaces in humid atmospheres: Influence of capillary condensation on surface deformation and adhesion", J. Phys. Chem. B, Vol. 107, p. 3774, 2003. https://doi.org/10.1021/jp0265992
  11. S. Kim and J. E. Curry, "Thin Films: Preparation, Characterization and Applications", Kluwer Academic/Plenum, New York, 2002.
  12. S. Kim, K. Cho, and J. E. Curry, "Measurements of the thickness compressibility of an n-octadecyltriethoxysilane monolayer self-assembled on mica", Langmuir, Vol. 21, p. 8290, 2005. https://doi.org/10.1021/la050689r
  13. I. Doudevski, W. A. Hayes, J. T. Woodward, and D. K. Schwartz, "Atomic force microscope imaging of molecular aggregation during self-assembled monolayer growth", Colloids Surf. A , Vol. 174, p. 233, 2000. https://doi.org/10.1016/S0927-7757(00)00514-8
  14. J. L. Parker, H. K. Christenson, and B. W. Ninham, "Device for measuring the force and separation between two surfaces down to molecular separations", Rev. Sci. Instrum., Vol. 60, p. 3135, 1989. https://doi.org/10.1063/1.1140544
  15. J. N. Israelachvili and G. E. Adams, "Measurement of forces between two mica surfaces in aqueous electrolyte solutions in the range 0-100 nm", J. Chem. Soc. Faraday Trans., Vol. 74, p. 975, 1978. https://doi.org/10.1039/f19787400975
  16. Y. L. Chen and J. N. Israelachvili, "Entropic forces between amphiphilic surfaces in liquids", J. Phys. Chem,. Vol. 96, p. 7752, 1992. https://doi.org/10.1021/j100198a048