Ordered bicontinuous nanoporous and nanorelief ceramic films from serf assembling polymer precursors

Science

Volumn 286, Issue 5445, 1999, Pages 1716-1719

  Chan, Vanessa Z H ^a   Hoffman, James ^b   Lee, Victor Y ^c   Iatrou, Hermis ^d   Avgeropoulos, Apostolos ^d   Hadjichristidis, Nikos ^d   Miller, Robert D ^c   Thomas, Edwin L ^a  

^a USA   (United States)

^b MATHEMATICAL SCIENCES RESEARCH INSTITUTE   (United States)

^c IBM ALMADEN RESEARCH CENTER   (United States)

^d UNIVERSITY OF ATHENS   (Greece)

Author keywords

[No Author keywords available]

Indexed keywords

HYDROCARBON; POLYMER; SILICON DERIVATIVE;

ARTICLE; CERAMICS; CHEMICAL MODIFICATION; FILM; OXIDATION; POROSITY; PRIORITY JOURNAL; ULTRAVIOLET IRRADIATION;

EID: 0033607502     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.286.5445.1716     Document Type: Article

References (32)

1. A. Monnier et al., Science 261, 1299 (1993).
2. L. Sierra, B. Lopez, H. Gil, J.-L. Guth, Adv. Mater. 11, 4 (1999); M. J. Kim and R. Ryoo, Chem. Mater. 11, 487 (1999); M. S. Morey, A. Davidson, G. D. Stucky, J. Por. Mater. 5, 195 (1998).
3. L. Sierra, B. Lopez, H. Gil, J.-L. Guth, Adv. Mater. 11, 4 (1999); M. J. Kim and R. Ryoo, Chem. Mater. 11, 487 (1999); M. S. Morey, A. Davidson, G. D. Stucky, J. Por. Mater. 5, 195 (1998).
4. L. Sierra, B. Lopez, H. Gil, J.-L. Guth, Adv. Mater. 11, 4 (1999); M. J. Kim and R. Ryoo, Chem. Mater. 11, 487 (1999); M. S. Morey, A. Davidson, G. D. Stucky, J. Por. Mater. 5, 195 (1998).
5. M. Templin et al., Science 278, 1795 (1997).
6. Y. Wei et al., Adv. Mater. 3, 313 (1998).
7. S. Johnson, P. J. Ollivier, T. E. Mallouk, Science 283, 963, (1999); D. Zhao et al., Science, 279, 548 (1998).
8. S. Johnson, P. J. Ollivier, T. E. Mallouk, Science 283, 963, (1999); D. Zhao et al., Science, 279, 548 (1998).
9. For example, a linear ABC tercopolymer exhibits a "knitting pattern" structure with c2mm symmetry [U. Breiner, U. Krappe, E. L. Thomas, R. Stadler, Macromolecules 31, 135 (1998)] and a star ABC tercopolymer displays a 2D structure with an intricate tessellation of p6mm symmetry defined by triangles, rectangles, and circles [S. Sioula, N. Hadjichristidis, E. L. Thomas, Macromolecules 31, 8429 (1998)].
10. For example, a linear ABC tercopolymer exhibits a "knitting pattern" structure with c2mm symmetry [U. Breiner, U. Krappe, E. L. Thomas, R. Stadler, Macromolecules 31, 135 (1998)] and a star ABC tercopolymer displays a 2D structure with an intricate tessellation of p6mm symmetry defined by triangles, rectangles, and circles [S. Sioula, N. Hadjichristidis, E. L. Thomas, Macromolecules 31, 8429 (1998)].
11. D. A. Hajduk et al., Macromolecules 27, 4063 (1994).
12. The anionic synthesis and characterization of the polymers are reported in A. Avgeropoulos et al., Chem. Mater. 10, 2109 (1998).
13. The monomer (PMDSS) contains 24 weight % Si, which is much higher than the critical 10 weight % needed to form a coherent oxide when exposed to an oxygen plasma [E. Reichmanis and C. Smolinksy, SPIE 469, 38 (1984)]. Because the silicon is intrinsically present in the monomer, the etch selectivity is also intrinsic in the block copolymer, so no postpolymerization chemistry is necessary, unlike hydrocarbon materials used previously by other groups [A. H. Gabor and C. K. Ober, Microelectronics Technology: Polymers for Advanced Imaging and Packaging, E. Reichmanis, Ed. (ACS Symposium Series 614, American Chemical Society, Washington, DC, 1995), chap. 19; M. Park, C. Harrison, P. M. Chaikin, R. A. Register, D. H. Adamson, Science 276, 1401 (1997)].
14. The monomer (PMDSS) contains 24 weight % Si, which is much higher than the critical 10 weight % needed to form a coherent oxide when exposed to an oxygen plasma [E. Reichmanis and C. Smolinksy, SPIE 469, 38 (1984)]. Because the silicon is intrinsically present in the monomer, the etch selectivity is also intrinsic in the block copolymer, so no postpolymerization chemistry is necessary, unlike hydrocarbon materials used previously by other groups [A. H. Gabor and C. K. Ober, Microelectronics Technology: Polymers for Advanced Imaging and Packaging, E. Reichmanis, Ed. (ACS Symposium Series 614, American Chemical Society, Washington, DC, 1995), chap. 19; M. Park, C. Harrison, P. M. Chaikin, R. A. Register, D. H. Adamson, Science 276, 1401 (1997)].
15. The monomer (PMDSS) contains 24 weight % Si, which is much higher than the critical 10 weight % needed to form a coherent oxide when exposed to an oxygen plasma [E. Reichmanis and C. Smolinksy, SPIE 469, 38 (1984)]. Because the silicon is intrinsically present in the monomer, the etch selectivity is also intrinsic in the block copolymer, so no postpolymerization chemistry is necessary, unlike hydrocarbon materials used previously by other groups [A. H. Gabor and C. K. Ober, Microelectronics Technology: Polymers for Advanced Imaging and Packaging, E. Reichmanis, Ed. (ACS Symposium Series 614, American Chemical Society, Washington, DC, 1995), chap. 19; M. Park, C. Harrison, P. M. Chaikin, R. A. Register, D. H. Adamson, Science 276, 1401 (1997)].
16. For the PI-DG sample, unstained ozone-etched microtomed sections could not be imaged because upon soaking in deionized water, the thin section broke apart because of the fragility of the P(PMDSS) networks. However, if thicker, coherent films supported on silicon wafers are etched, the struts remain intact after removal of the matrix (15).
17. Available at www.msri.org/people/staff/jim.
18. C. A. Lambert, L. H. Radzilowski, E. L. Thomas, Philos. Trans. R. Soc. London Ser. A 354, 2009 (1996).
19. 2 1.9 cm away from the light source.
20. 2 but the directionality of the plasma etch is problematic for the 3D double gyroid structure. A plasma asher that does not contain a forward bias or the use of higher gas pressures in the oxygen reactive ion etcher are ways to reduce the directionality of the plasma process.
21. P(PMDSS) homopolymer was spincast from a 5 wt% solution in toluene onto Si(100) wafers. The solution was directly filtered onto the wafers by using a syringe equipped with a 0.2-μm filter. The samples were then annealed in a vacuum oven at 60°C to drive off excess toluene. The resulting thickness of these samples was 200 nm as measured by profilometry. The samples were then exposed to the same ozone + UV process (see above).
22. J. H. Greiner, J. Appl. Phys. 42, 5151 (1971).
23. The uneven surface prevented the measurement of refractive index or thickness because measured values varied greatly depending on where the measurement was taken.
24. In the current production of high-temperature coatings, silicon-containing homopolymers are pyrolyzed at high temperatures (T > 600°C) in order to produce silicon oxycarbide [V. Belot, R. J. P. Corriu, D. Leclercq, P. H. Mutin, A. Vioux, J. Non-Cryst. Solids 176, 33 (1994)]. The oxidized P(PMDSS) homopolymer itself could have utility as high-temperature coatings for materials such as fibers.
25. T. Hashimoto, K. Tsutsumi, Y. Funaki, Langmuir 13, 6869 (1997).
26. J. S. Lee, A. Hirao, S. Nakahama, Macromolecules 22, 2602 (1989).
27. V. Z.-H Chan et al., U.S. and PCT patent PCT/US99/ 15068.
28. D. J. Kinning, E. L. Thomas, J. M. Ottino, Macromolecules 20, 1129 (1987).
29. www.itrs.net/ntrs/publntrs.nsf
30. J. Joannopoulos, Photonic Crystals: Molding the Flow of Light (Princeton Univ. Press, Princeton, NJ, 1995); A. Urbas, Y. Fink, E. L. Thomas, Macromolecules 32, 4748 (1999).
31. J. Joannopoulos, Photonic Crystals: Molding the Flow of Light (Princeton Univ. Press, Princeton, NJ, 1995); A. Urbas, Y. Fink, E. L. Thomas, Macromolecules 32, 4748 (1999).
32. We thank R. J. Composto and H. Wang for help with RBS experiments and P. Derege for helpful discussions. The NSF MRSEC shared experimental facilities at MIT were used. Funding was provided by Air Force Office of Scientific Research-ASSERT No. F49 620-94-1-0357, by the NSF Center for Polymer Interfaces and Macromolecular Assemblies (CPIMA) at IBM, and by NSF and IBM through graduate research fellowships for V.Z.-H.C., who also thanks S. Adams for inspiration.