Dispersion of nano-sized gold particles into polymers: dependence on terminal groups of polymers and morphology of vapor-deposited gold

Abstract

Dispersion of nano-sized gold particles into polymers was investigated from the viewpoint of terminal groups and molecular motion of the matrix polymers, and from morphology of vapor-deposited gold. NH₂-terminated poly(ethylene oxide) (PEO-NH₂) and poly(ethylene glycol) (PEG) were used as the matrix polymers. When gold with a thickness of 20 nm was vapor-deposited onto a melt of PEO-NH₂ at 60 °C, nano-sized gold particles were smoothly dispersed into the melt. On the other hand, gold vapor-deposited on a melt of PEG formed only conglomerates. When gold with a thickness of 3 nm was vapor-deposited onto PEO-NH₂ and PEG films kept at 20 °C, it formed particulate films. The gold particles formed were not dispersed into the polymer films by heat-treatment below the melting point of the polymer. However, when the polymer films were melted by heat-treatment at 50 °C, the gold particles were dispersed only into PEO-NH₂. When gold with a thickness of 20 nm was vapor-deposited on the polymer films, it formed conglomerates, therefore the dispersion of gold particles into both polymers was not observed even upon heat-treatment at 50 °C. Measurements of spin-spin relaxation time by solid-state ¹H NMR indicated that the molecular motion of PEO-NH₂ was restricted below the melting point. Therefore, the dispersion of the nano-sized particles occurred only above the melting point of PEO-NH₂.

References

1. G. Schmid, Chem. Rev., 1992, 92, 1709.
2. P. Ball and L. Garwin, Nature, 1992, 355, 761.
3. J. S. Bradley, in Clusters and Colloids. From Theory to Applications, ed. G. Schmid, VCH, Weinheim, 1994.
4. U. Kreibig and M. Voller, in Optical Properties of Metal Clusters, Springer-Verlag, Berlin, 1995.
5. H. Hirai and N. Toshima, in Tailored Metal Catalysts, ed. Y. Iwasawa, Reidel, Dordrecht, 1986.
6. N. Toshima, M. Harada, Y. Yamazaki and K. Asakura, J. Phys. Chem., 1992, 96, 9927.
7. D. G. Duff, P. P. Edwards and B. F. G. Johnson, J. Phys. Chem., 1995, 99, 15934.
8. L. Longenberger and G. Mills, J. Phys. Chem., 1995, 99, 475.
9. A. B. R. Mayer and J. E. Mark, Eur. Polym. J., 1998, 34, 103.
10. S. Ogawa, Y. Hayashi, N. Kobayashi, T. Tokizaki and A. Nakamura, Jpn. J. Appl. Phys., 1994, 33, L331.
11. Y. N. C. Chan, W. G. S. Craig, R. R. Schrock and R. E. Cohen, Chem. Mater., 1992, 4, 885.
12. Y. Nakao, J. Colloid Interface Sci., 1995, 171, 386.
13. T. Noguchi, K. Gotoh, Y. Yamaguchi and S. Deki, J. Mater. Sci. Lett., 1991, 10, 477.
14. K. Akamatsu and S. Deki, J. Mater. Chem., 1997, 7, 1773.
15. K. Akamatsu and S. Deki, J. Mater. Chem., 1998, 8, 637.
16. J. A. Williams, G. E. Rindone and H. A. McKinstry, J. Am. Ceram. Soc., 1981, 64, 709.
17. H. Tanaka and T. Nishi, J. Chem. Phys., 1986, 85, 6197.
18. R. Folland and A. Cherlesby, Polymer, 1979, 20, 207.
19. D. W. McCall, Acc. Chem. Res., 1971, 4, 223.