charge, thus giving rise to the formation of alarge microporous single crystal.In conclusion, we report here an exampleof direct, bottom-up synthesis of single cal-cite crystals with controlled orientation andmicrostructure. Our results suggest a generalstrategy for the design of micro- and nanopat-terned crystalline materials: utilization ofamorphous-to-crystalline transitions using spe-cially designed structural templates with inte-grated nucleation sites. In our approach, thechosen micropatterned substrate not onlydetermines the microstructure, but also isinvolved in the release of stresses and impuri-ties during the formation of the final crystal.The possible applications of q2D or 3Dtemplates may include the direct growth ofdefect-free micropatterned crystals, the relax-ation of stresses encountered during amor-phous-to-crystalline transitions in existing ma-terials, and controlled solvent release duringpolycondensation reactions (1, 2, 32). Suchconcept transfer could perfect our ability tomake nanostructured materials for a wide vari-ety of applications and shed light on fundamen-tal mechanisms that regulate nano- and mi-croscale phenomena in biomineralization.References and Notes1. A. Gonis, Ed., Nucleation and Growth Processes inMaterials (Materials Research Society, Boston, 2000).2. A. W. Vere, Crystal Growth: Principles and Progress(Updates in Applied Physics and Electrical TechnologySeries, Plenum, New York, 1988).3. H. A. Lowenstam, S. Weiner, On Biomineralization(Oxford Univ. Press, Oxford, 1989).4. L. Addadi, S. Weiner, Angew. Chem. Int. Ed. Engl. 31,153 (1992).5. F. H. Wilt, J. Struct. Biol. 126, 216 (1999).6. J. Aizenberg, A. Tkachenko, S. Weiner, L. Addadi, G.Hendler, Nature 412, 819 (2001).7. E. Beniash, J. Aizenberg, L. Addadi, S. Weiner, Proc. R.Soc. London Ser. B 264, 461 (1997).8. E. Beniash, L. Addadi, S. Weiner, J. Struct. Biol. 125,50 (1999).9. I. M. Weiss, N. Tuross, L. Addadi, S. Weiner, J. Exp.Zool. 293, 478 (2002).10. N. Koga, Y. Z. Nakagoe, H. Tanaka, Thermochim. Acta318, 239 (1998).11. S. Raz, S. Weiner, L. Addadi, Adv. Mater. 12,38(2000).12. E. Loste, F. C. Meldrum, Chem. Commun., 901 (2001).13. J. Aizenberg, G. Lambert, S. Weiner, L. Addadi, J. Am.Chem. Soc. 124, 32 (2002).14. M. Alper, P. D. Calvert, R. Frankel, P. C. Rieke, D. A.Tirrell, Materials Synthesis Based on Biological Pro-cesses (Materials Research Society, Pittsburgh, 1991).15. A. H. Heuer et al., Science 255, 1098 (1992).16. S. Mann et al., Science 261, 1286 (1993).17. T. Douglas et al., Science 269, 54 (1995).18. J. H. Fendler, Chem. Mater. 8, 1616 (1996).19. S. Mann, G. A. Ozin, Nature 382, 313 (1996).20. S. I. Stupp, P. V. Braun, Science 277, 1242 (1997).21. A. M. Belcher, P. K. Hansma, G. D. Stucky, D. E. Morse,Acta Mater. 46, 733 (1998).22. H. L. Merten, G. L. Bachman, U.S. Patent 4,237,147(1980).23. K. Sawada, Pure Appl. Chem. 69, 921 (1997).24. L. B. Gower, D. J. Odom, J. Cryst. Growth 210, 719(2000).25. G. F. Xu, N. Yao, I. A. Aksay, J. T. Groves, J. Am. Chem.Soc. 120, 11977 (1998).26. A. Kumar, N. L. Abbott, E. Kim, H. A. Biebuyck, G. M.Whitesides, Acc. Chem. Res. 28, 219 (1995).27. J. Aizenberg, A. J. Black, G. M. Whitesides, Nature 398,495 (1999).28.㛬㛬㛬㛬 , J. Am. Chem. Soc. 121, 4500 (1999).29. Video clips and TEM data are presented as supportingonline material on Science Online.30. H. H. Teng, P. M. Dove, C. A. Orme, J. J. De Yoreo,Science 282, 724 (1998).31. A detailed Raman, EDX, and fluorescence microscopystudy of the incorporation of impurities will be re-ported elsewhere.32. T. P. L. Pedersen et al., Appl. Phys. Lett. 79, 3597(2001).33. We thank L. Addadi, S. Weiner, and G. M. Whitesidesfor constructive discussions.Supporting Online Materialwww.sciencemag.org/cgi/content/full/299/5610/1205/DC1Fig. S1Movies S1 and S28 October 2002; accepted 20 December 2002Giant Supramolecular LiquidCrystal LatticeGoran Ungar,1* Yongsong Liu,1Xiangbing Zeng,1Virgil Percec,2Wook-Dong Cho2Self-organized supramolecular organic nanostructures have potential applica-tions that include molecular electronics, photonics, and precursors for nano-porous catalysts. Accordingly, understanding how self-assembly is controlled bymolecular architecture will enable the design of increasingly complex struc-tures. We report a liquid crystal (LC) phase with a tetragonal three-dimensionalunit cell containing 30 globular supramolecular dendrimers, each of which isself-assembled from 12 dendron (tree-like) molecules, for the compoundsdescribed here. The present structure is one of the most complex LC phases yetdiscovered. A model explaining how spatial arrangement of self-assembleddendritic aggregates depends on molecular architecture and temperature isproposed.Molecular self-assembly into a variety ofbulk phases with two-dimensional (2D) and3D nanoscale periodicity, such as cubic, cy-lindrical, or mesh phases, has been re-searched intensely in lyotropic (e.g., surfac-tant-water) LCs (1), block copolymers (2–4),and thermotropic (solvent-free) LCs (5, 6).Lyotropics can provide templates for porousinorganic materials with well-defined struc-tures (7), and LC complexes of DNA withcationic and neutral lipids are potential carri-ers for gene delivery (8). Complex organicnanostructures (9, 10) may serve as scaffoldsfor photonic materials (11) and other nanoar-rays (12) and for surface nanopatterning (13).In the case of bicontinuous cubic phases (1, 2,5), the same structures have been observed inlyotropics, thermotropics, and block copoly-mers. The recent inclusion of self-assemblingdendrons into the category of nanostructuredsoft matter (14 ) has shown their taperedshape to be responsible for creating similarbulk phases (13, 15–18) and enabling “self-processing” of electronics components (19).It has also become apparent that manipulatingthe size and distribution of “micelles” aggre-gated from self-assembling dendrons can beused in controlling polymerization (16 ). Re-garding creation of structural diversity, den-dron shape can be fine-tuned in ways unavail-able in lyotropic LCs or block copolymers(14), and hence have the potential of forminghitherto unobserved phases. Here, we report ahighly complex noncubic phase and developa relationship between chemical structure andthe self-assembly mode of tapered dendrons.We concentrate on compounds I and II,labeled [4-3,4,5-(3,5)2]12G3-X in (20)(Scheme 1), where X is CH2OH and COOH,respectively. However, we have also ob-served the x-ray signature of
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