Hostname: page-component-8448b6f56d-42gr6 Total loading time: 0 Render date: 2024-04-23T07:33:23.374Z Has data issue: false hasContentIssue false

Stress induced phase transition in a monomolecular perfluroalkylsilane film self assembled on aluminium surface

Published online by Cambridge University Press:  01 February 2011

Sanjay Kumar Biswas
Affiliation:
skbis@mecheng.iisc.ernet.in, Indian Institute of Science, Mechanical Engineering, C.V.Raman Avenue, Bangalore, Karnataka, 560012, India, 91 80 22932589, 91 80 23600648
D. Devaprakasam
Affiliation:
Indian Institute of Science, Mechanical Engineering, India
Get access

Abstract

We control the stiffnesses of two dual double cantelevers placed in series to control penetration into a perflurooctyltrichlorosilane monolayer self assembled on aluminium and silicon substrates. The top cantilever which carries the probe is displaced with respect to the bottom cantilever which carries the substrate, the difference in displacement recorded using capacitors gives penetration. We further modulate the input displacement sinusoidally to deconvolute the viscoelastic properties of the monolayer. When the intervention is limited to the terminal end of the molecule there is a strong viscous response in consonance with the ability of the molecule to dissipate energy by the generation of gauche defects freely. When the intervention reaches the backbone, at a contact mean pressure of 0.2GPa the damping disappears abruptly and the molecule registers a steep rise in elastic modulus and relaxation time constant, with increasing contact pressure. We offer a physical explanation of the process and describe this change as due to a phase transition from a liquid like to a solid like state.

Type
Research Article
Copyright
Copyright © Materials Research Society 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Berman, A. D. and Israelachvili, J. N., in Modern Tribology Handbook, Bhushan, B. (CRC Press, London, 2001), pp. 568600.Google Scholar
2. Demirel, A. L. and Granick, S., Phys. Rev. Lett. 77, 2261 (1996).Google Scholar
3. Du, Q., Xiao, X.-d., Charych, D., Wolf, F., Frantz, P., Shen, Y. R., and Salmeron, M., Phys. Rev. B 51, 7456 (1995).Google Scholar
4. Carpick, R. W. and Salmeron, M., Chem. Rev. (Washington, D.C.) 97, 1163 (1997).Google Scholar
5. Quon, R. A., Ulman, A., and Vanderlick, T. K., Langmuir 16, 3797 (2000).Google Scholar
6. Joyce, S. A., Thomas, R. C., Houston, J. E., Michalske, T. A., and Crooks, R. M., Phys. Rev. Lett. 68, 2790 (1992).Google Scholar
7. Siepmann, J. I. and McDonald, I. R., Phys. Rev. Lett. 70, 453 (1993).Google Scholar
8. Devaprakasam, D., Sampath, S., and Biswas, S. K., Langmuir 20, 1329 (2004).Google Scholar
9. Devaprakasam, D. and Biswas, S. K., Rev. Sci. Instrum. 74, 1228 (2003).Google Scholar
10. Devaprakasam, D. and Biswas, S. K., Rev. Sci. Instrum. 76, 035102 (2005).Google Scholar
11. Lucas, B. N., Rosenmeyer, C. T., and Oliver, W. C. (unpublished).Google Scholar
12. Maugis, D., Contact, Adhesion and Rupture of Elastic Solids (Springer, Berlin, 1999).Google Scholar
13. Leng, Y. and Jiang, S., J. Chem. Phys. 113, 8800 (2000).Google Scholar
14. Owens, D. K. and Wendt, R. C., J. Appl. Polym. Sci. 13, 1741(1969).Google Scholar
15. Tutein, A. B., Staurt, S. J., and Harrison, J. A., J. Phys. Chem. B 103, 11357 (1999).Google Scholar
16. Peachey, J., Van Alsten, J., and Granick, S., Rev. Sci. Instrum. 62, 643 (1991).Google Scholar
17. Shinn, N. D., Mayer, T. M., and Michalske, T. A., Tribol. Lett. 7, 67 (1999).Google Scholar
18. Mikulski, P. T. and Harrison, J. A., J. Am. Chem. Soc. 123, 6873 (2001).Google Scholar
19. Jeffery, S., Hoffmann, P. M., Pethica, J. B., Ramanujan, C., Ozer, H. O., and Oral, A., Phys. Rev. E 69, 046118 (2004).Google Scholar