2
50 Communications to the Editor
Macromolecules, Vol. 37, No. 2, 2004
Ack n ow led gm en t. Financial support from the Na-
tional Science Foundation (NSF-NIRT and the NSF-
STC Program under Agreement DMR-0120967) and the
Air Force Office of Scientific Research (AFOSR) under
the MURI Center on Polymeric Smart Skins is acknowl-
edged. Alex K.-Y. J en thanks the Boeing-J ohnson
Foundation for its support.
Su p p or tin g In for m a tion Ava ila ble: Text giving detailed
experimental information for material preparation and struc-
tural characterization. This material is available free of charge
via the Internet at http://pubs.acs.org.
Refer en ces a n d Notes
(
1) Shi, Y.; Zhang, C.; Zhang, H.; Bechtel, J . H.; Dalton, L. R.;
Robinson, B. H.; Steier, W. H. Science 2000, 288, 119. (b)
Lee, M.; Katz, H. E.; Erben, C.; Gill, D. M.; Gopalan, P.;
Heber, J . D.; McGee, D. J . Science 2002, 298, 1401. (c)
Marder, S. R.; Kippelen, B.; J en, A. K.-Y.; Peyghambarian,
N. Nature (London) 1997, 388, 845. (d) Marks, T. J .; Ratner,
M. A. Angew. Chem., Int. Ed. Engl. 1995, 34, 155. (e)
Burland, D. M.; Miller, R. D.; Walsh, C. A. Chem. Rev. 1994,
94, 31. (f) Kajzar, F.; Lee, K.-S.; J en, A. K.-Y. Adv. Polym.
Sci. 2003, 161, 1.
F igu r e 2. Temporal stability of E-O activity of PI-CLD at
8
5 °C.
7
1 pm/V. This high r33 value represents ∼81% of the
highest achievable r33 value (88 pm/V) that is predicted
by using the two-level model.12 Most importantly, when
compared to the flexible polymer P S-CLD, the similar
high poling efficiency (∼80% of the theoretically achiev-
able E-O activity) has been reproduced in high Tg and
rigid polymer P I-CLD.
(
2) Ma, H.; Liu, S.; Luo, J .; Suresh, S.; Liu, L.; Kang, S. H.;
Haller, M.; Sassa, T.; Dalton, L. R.; J en, A. K.-Y. Adv. Funct.
Mater. 2002, 12, 565.
(
3) Luo, J .; Ma, H.; Haller, M.; J en, A. K.-Y.; Barto, R. R. Chem.
Moreover, this high-Tg P I-CLD exhibits a much
improved alignment stability compared to that of P S-
CLD. The poled P I-CLD retains higher than 90% of
its original r33 value after more than 600 h at 85 °C
Commun. 2002, 888.
(4) Robinson, B. H.; Dalton, L. R.; Harper, H. W.; Ren, A.; Wang,
F.; Zhang, C.; Todorova, G.; Lee, M.; Aniszfeld, R.; Garner,
S.; Chen, A.; Steier, W. H.; Houbrecht, S.; Persoons, A.;
Ledoux, I.; Zyss, J .; J en, A. K.-Y. Chem. Phys. 1999, 245,
(Figure 2). For comparison, the flexible polymer P S-
3
5. (b) Robinson, B. H.; Dalton, L. R. J . Phys. Chem. A 2000,
CLD with a much lower Tg (90 °C) shows only 37% of
its original r33 value after heating at 70 °C for 144 h.
The structural features of P I-CLD can explain very
well for its high poling efficiency and excellent thermal
stability. This cardo-type polyimide has a rigid and 3-D
extended main chain, and along the V-bended repeating
units, the dendronized chromophores are attached on
the fluorene ring that is perpendicular to the imido
backbone. This kind of spatial arrangement can sup-
press strong interchain interactions of polyimide and
reduce potential phase separation between the highly
aromatic, rigid polyimide backbone and chromophores.
In addition, the cardo-type linkage of the dendronized
chromophores may also facilitate the self-assembly of
these NLO molecules to form potentially ordered cylin-
drical rigid rods which will facilitate the dipole align-
ment during the poling process because less steric
hindrance caused by chromophore/polymer chain en-
tanglements.
In conclusion, we have successfully applied the site-
isolation principle to a rigid 3-D cardo-type polyimide
with very high Tg. High poling efficiency has been
achieved to afford a very large E-O coefficient (71 pm/V
at 1.3 µm). More than 90% of this value can be retained
at 85 °C for more than 650 h. Comprehensive studies
to optimize the properties of these high-Tg materials for
E-O device fabrication are in progress.
104, 4785. (c) Dalton, L. R.; Steier, W. H.; Robinson, B. H.;
Zhang, C.; Ren, A.; Garner, S.; Chen, A.; Londergan, T.;
Irwin, L.; Carlson, B.; Fifield, L.; Phelan, G.; Kincaid, C.;
Amend, J .; J en, A. K.-Y. J . Mater. Chem. 1999, 9, 19.
5) Ma, H.; J en, A. K.-Y. Adv. Mater. 2001, 13, 1201.
(6) Ma, H.; Chen, B. Q.; Sassa, T.; Dalton, L. R.; J en, A. K.-Y.
J . Am. Chem. Soc. 2001, 123, 986.
7) Luo, J .; Liu, S.; Haller, M.; Lu, L.; Ma, H.; J en, A. K.-Y.
(
(
Adv. Mater. 2002, 14, 1763.
(
8) Verbiest, T.; Burland, D. M.; J urich, M. C.; Lee, V. Y.; Miller,
R. D.; Volksen, W. Science 1995, 268, 1604. (b) Saadeh, H.;
Yu, D.; Wang, L. M.; Yu, L. P. J . Mater. Chem. 1999, 9, 1865.
(
1
c) Chen, T. A.; J en, A. K.-Y.; Cai, Y. M. J . Am. Chem. Soc.
995, 117, 7295. (d) Davey, M. H.; Lee, V. Y.; Wu, L.-M.;
Moylan, C. R.; Volksen, W.; Knoesen, A.; Miller, R. D.;
Marks, T. J . Chem. Mater. 2000, 12, 1679.
(9) Korshak, V. V.; Vinogradova, S. V.; Vygodskii, Y. S. J .
Macromol. Sci., Rev. Macromol. Chem. Part C 1974, 11, 45.
(b) Yang, C. P.; Lin, J . H. J . Polym. Sci., Part A: Polym.
Chem. 1993, 31, 2153. (c) Hsiao, S. H.; Li, C. T. J . Polym.
Sci., Part A: Polym. Chem. 1999, 37, 1403.
(
10) Zhang, C.; Dalton, L. R.; Oh, M.-C.; Zhang, H.; Steier, W.
H. Chem. Mater. 2001, 13, 3043. (b) Liakatas, I.; Cai, C.;
Bosch, M.; J ager, M.; Bosshard, Ch.; Gunter, P.; Zhang, C.;
Dalton, L. R. Appl. Phys. Lett. 2000, 76, 1368.
11) Teng, C. C.; Man, H. T. Appl. Phys. Lett. 1990, 56, 1734.
12) Katz, H. E.; Dirk, C. W.; Schilling, M. L.; Singer, K. D.; Sohn,
J . E. Mater. Res. Soc. Symp. Proc. 1987, 109, 127. The r33
value at 1.55 µm is 58 pm/V estimated from the same two-
level model using the experimental value of 71 pm/V at 1300
nm.
(
(
MA0350009