Supramolecular materials: Self-organized nanostructures

Science

Volumn 276, Issue 5311, 1997, Pages 384-389

  Stupp, S I ^a   LeBonheur, V ^a   Walker, K ^a   Li, L S ^a   Huggins, K E ^a   Keser, M ^a   Amstutz, A ^a  

^a UNIVERSITY OF ILLINOIS AT URBANA CHAMPAIGN   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

COPOLYMER; NANOPARTICLE;

ADHESION; ARTICLE; CHEMICAL STRUCTURE; CRYSTALLIZATION; FILM; OPTICS; POLYMERIZATION; PRIORITY JOURNAL; STRENGTH; SURFACE PROPERTY; SYNTHESIS;

BASIDIOMYCOTA;

EID: 0030973593     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.276.5311.384     Document Type: Article

References (33)

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13. Benzene (90% by volume) and THF (10% by volume) were used as the polymerization solvents. THF was added to break up the aggregates that n-butyl lithium forms in benzene [M. Morton, Anionic Polymerization: Principles and Practice (Academic Press, New York, 1983)], thus increasing the rate of styrene oligomerization. We carried out the reaction at RT, using standard Schlenk line techniques with a freeze-pump-thaw procedure of solvents before initiation.
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16. The esterifications in 1 are carried out under mild conditions developed by J. S. Moore and S. I. Stupp [Macromolecules 23, 65 (1990)]. The reaction uses DIPC and DPTS.
17. 2 units, hydrogen-pierced rings, and fused rings.
18. Before cross-linking, triblock molecules (1) form a birefringent solid at RT, which melts into a liquid crystal at about 130°C and undergoes isotropization at 262°C.
19. 4 as a standard staining procedure for the remaining double bonds in isoprene segments in order to improve contrast in electron microscopy. After staining, the Au-organic-C sandwich was microtomed with a diamond knife into sections 50 to 100 nm thick. Gold was necessary for this procedure because of its softness. Moreover, the flanking of the organic film by Au and C on opposite surfaces offered an excellent tracer that could be used to find the film under the electron beam. Also, ultramicrotoming of the thin films is possible only after the cross-linking reaction, which increases the mechanical integrity of the film. We also find that, after cross-linking, atomic force microscopy tips do not mechanically damage the film's surface.
20. The image-processing technique known as fast Fourier transform enhances the signal-to-noise ratio in TEM images by removing the coefficients of the Fourier transform at spatial frequencies that do not correspond to the periodic structure of a specimen [D. L. Misell, in Practical Methods in Electron Microscopy, A. M. Glauert, Ed. (North-Holland, New York, 1978), vol. 7; A. Rosenfeld and A. C. Kak, Digital Picture Processing (Academic Press, New York, ed. 2, 1982), vol. 1; J. C. Russ, The Image Processing Handbook, (CRC Press, Boca Raton, FL, ed. 2, 1995)]. We filtered coefficients of the transform corresponding to structural detail from those correspending to noise by multiplying the power spectrum by a "mask" having a value of unity near the coefficients of interest and zero elsewhere (the power spectrum is obtained from the fast Fourier transform of the digitized image and is analogous to an optical diffraction pattern).
21. The image-processing technique known as fast Fourier transform enhances the signal-to-noise ratio in TEM images by removing the coefficients of the Fourier transform at spatial frequencies that do not correspond to the periodic structure of a specimen [D. L. Misell, in Practical Methods in Electron Microscopy, A. M. Glauert, Ed. (North-Holland, New York, 1978), vol. 7; A. Rosenfeld and A. C. Kak, Digital Picture Processing (Academic Press, New York, ed. 2, 1982), vol. 1; J. C. Russ, The Image Processing Handbook, (CRC Press, Boca Raton, FL, ed. 2, 1995)]. We filtered coefficients of the transform corresponding to structural detail from those correspending to noise by multiplying the power spectrum by a "mask" having a value of unity near the coefficients of interest and zero elsewhere (the power spectrum is obtained from the fast Fourier transform of the digitized image and is analogous to an optical diffraction pattern).
22. The image-processing technique known as fast Fourier transform enhances the signal-to-noise ratio in TEM images by removing the coefficients of the Fourier transform at spatial frequencies that do not correspond to the periodic structure of a specimen [D. L. Misell, in Practical Methods in Electron Microscopy, A. M. Glauert, Ed. (North-Holland, New York, 1978), vol. 7; A. Rosenfeld and A. C. Kak, Digital Picture Processing (Academic Press, New York, ed. 2, 1982), vol. 1; J. C. Russ, The Image Processing Handbook, (CRC Press, Boca Raton, FL, ed. 2, 1995)]. We filtered coefficients of the transform corresponding to structural detail from those correspending to noise by multiplying the power spectrum by a "mask" having a value of unity near the coefficients of interest and zero elsewhere (the power spectrum is obtained from the fast Fourier transform of the digitized image and is analogous to an optical diffraction pattern).
23. L. H. Radzilowski, B. O. Carragher, S. I. Stupp, Macromolecules, in press.
24. J. F. Elman, B. D. Johs, T. E. Long, J. T. Koberstein, ibid. 27, 5341 (1994).
25. 2. The 1064-nm fundamental was produced by a Molectron MY34-20 Q-switched Nd:yttrium-aluminum-garnet laser with a 20-ns pulse width operating at a 20-Hz repetition rate. The second harmonic at 532 nm was separated from the fundamental by means of a series of green pass filters and an Instruments SA, Inc. DH-10 double monochromator. The light was collected in a Hamamatsu R1477 photomultiplier tube, and the signal was sent out to a digital data-acquisition system and an oscilloscope. All data were corrected for transmission of fundamental and absorption of the second harmonic.
26. K. Kumagi, G. Mizutani, H. Tsukioka, T. Yamauchi, S. Ushioda, Phys. Rev. B 48, 14488 (1993); D. Wilk, D. Johannsmann, C. Stanners, Y. R. Shen, ibid. 51, 10057 (1995); H. Hoshi, T. Yamada, K. Ishikawa, H. Takeoze, A. Fukuda, ibid. 52, 12335 (1995); ibid. 53, 12663 (1996).
27. K. Kumagi, G. Mizutani, H. Tsukioka, T. Yamauchi, S. Ushioda, Phys. Rev. B 48, 14488 (1993); D. Wilk, D. Johannsmann, C. Stanners, Y. R. Shen, ibid. 51, 10057 (1995); H. Hoshi, T. Yamada, K. Ishikawa, H. Takeoze, A. Fukuda, ibid. 52, 12335 (1995); ibid. 53, 12663 (1996).
28. K. Kumagi, G. Mizutani, H. Tsukioka, T. Yamauchi, S. Ushioda, Phys. Rev. B 48, 14488 (1993); D. Wilk, D. Johannsmann, C. Stanners, Y. R. Shen, ibid. 51, 10057 (1995); H. Hoshi, T. Yamada, K. Ishikawa, H. Takeoze, A. Fukuda, ibid. 52, 12335 (1995); ibid. 53, 12663 (1996).
29. K. Kumagi, G. Mizutani, H. Tsukioka, T. Yamauchi, S. Ushioda, Phys. Rev. B 48, 14488 (1993); D. Wilk, D. Johannsmann, C. Stanners, Y. R. Shen, ibid. 51, 10057 (1995); H. Hoshi, T. Yamada, K. Ishikawa, H. Takeoze, A. Fukuda, ibid. 52, 12335 (1995); ibid. 53, 12663 (1996).
30. -1.
31. S. Wu, Polymer Interface and Adhesion (Dekker, New York, 1985).
32. G. C. Pimentel and A. L. McClellan, The Hydrogen Bond (Freeman, San Francisco, 1960).
33. Supported by grants from the Office of Naval Research (N00014-96-1-0515). NSF (DMR 93-12601), and the Department of Energy (DEFG02-91ER45439 obtained through the Materials Research Laboratory of the University of Illinois). We appreciate the efforts of P. Braun in helping with contact angle experiments, and also those of R. Strange. We acknowledge the use of facilities at the University of Illinois Center for Electron Microscopy and the Visualization Laboratory of the Beckman Institute for Advanced Science and Technology.