tetraoctylammonium carboxylate in dry THF were added at once. A color change from orange to light yellow could be observed and the solution started to turn black due to colloid formation. After 4 h the solvent was re- moved in vacuo [10]. Received: December 17, 1998 Final version: January 22, 1999 ± [1] a) Clusters and Colloids: From Theory to Applications (Ed.: G. Schmid), VCH, Weinheim 1994. b) Nanoparticles and Nanostructured Films (Ed.: J. H. Fendler), Wiley-VCH, Weinheim 1998. c) A. Heng- lein, Ber. Bunsen-Ges. 1997, 101, 1562. d) G. Schmid, L. F. Chi, Adv. Mater. 1998, 10, 515. [2] Tetraalkylammonium-stabilized metal-colloids: a) J. Kiwi, M. Grätzel, J. Am. Chem. Soc. 1979, 101, 7214. b) Y. Sasson, A. Zoran, J. Blum, J. Mol. Catal. 1981, 11, 293. c) M. Boutonnet, J. Kizling, P. Stenius, G. Maire, Colloids Surf. 1982, 5, 209. d) N. Toshima, T.Takahashi, H. Hi- rai, Chem. Lett. 1985, 1245. e) M. Boutonnet, J. Kizling, R. Touroude, G. Maire, P. Stenius, Appl. 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Chem. 1969, 81, 206. [4] It is not straightforward to assess or to compare the relative reducing power of such different reductants as H 2 , NaBH 4 , [Et 3 BH] ± [R 4 N] + , hy- drazine or alcohols used in metal colloid syntheses [1]. [5] J. S. Bradley in Clusters and Colloids: From Theory to Applications (Ed.: G. Schmid), VCH, Weinheim 1994, p. 459. [6] In our electrochemical method for the formation of stabilized metal colloids, current density plays a certain role [2j], but other parameters such as electrode distance, temperature and solvent polarity are more important [M. T. Reetz, M. Winter, unpublished]. [7] The variation of alcohols as reductants of certain transition metal salts leads to metal colloids of different sizes, although the range is rather small. Moreover, opposite trends are observed, depending upon the na- ture of the metal: a) G. W. Busser, J. G. von Ommen, J.A. Lercher in Adv. Catal. Nanostruct. Mater. (Ed.: W. R. Moser), Academic, San Die- go 1996, p. 213. b) T. Teranishi, M. Miyake, Chem. Mater. 1998, 10, 594. [8] The reduction of metal salts in micelles allows for an elegant way to control particle size in many cases: a) M. Antonietti, F. Gröhn, J. Hart- mann, L. Bronstein, Angew. Chem. Int. Ed. Engl. 1997, 36, 2080; An- gew. Chem. 1997, 109, 2170. b) M. P. Pileni, Ber. Bunsen-Ges. 1997, 101, 1578. [9] The observed shift of the UV/vis-absorption from 411 nm [Pd(OAc) 2 ] to shorter wavelengths (<400 nm; palladium acetate containing com- plexes) at the beginning of the synthesis indicates ligand exchange. [10] If necessary, a portion of the ammonium salt can be removed by washing with ethanol which raises the metal contents from 30±40 % to 80 %. [11] Using a system developed by M. T. Reetz, M. Maase, B. Tesche and T. Schilling (Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr), the TEM micrographs (negatives) were scanned at a physical resolution of 1200 dpi (HP Scanjet 4C/T) and the digitized images ana- lyzed by means of digital image reprocessing. [12] It was not possible to obtain reversible cyclic voltammograms of car- boxylates (n-C 8 H 17 ) 4 N + (RCO 2 ± ) because the radicals RCO 2 ± undergo rapid irreversible decarboxylation. Therefore, the peak potentials E p(Ox) of oxidation were measured (vs. Ag/AgNO 3 -electrode in THF). We thank E. Janssen for carrying out these experiments. [13] This was observed, for example, in the formation of nanostructured CdS-particles: H. Weller, Angew. Chem. Int. Ed. Engl. 1993, 32, 41; Angew. Chem. 1993, 105, 43. [14] M.A. Watzky, R. G. Finke, J. Am. Chem. Soc. 1997, 119, 10382. [15] This term was introduced by Finke [14]; the phenomenon was pre- viously observed in other systems: a) D. G. Duff, A. Baiker in Prepara- tion of Catalysts VI: Scientific Bases for the Preparation of Heterogene- ous Catalysts (Eds: G. Poncelet, J. Martens, B. Delmon, P. A. Jacobs, P. Grange), Stud. Surf. Sci. Catal., Vol. 91, Elsevier, Amsterdam 1995, p.505. b) K. R. Brown, M. J. Natan, Langmuir 1998, 14, 726. c) The formation of CdS-nanoparticles also represents a living polymerization [13]. Supramolecular Polymeric Materials with Hierarchical Structure-Within-Structure Morphologies** By Janne Ruokolainen, Gerrit ten Brinke,* and Olli Ikkala* Polymeric materials containing structure-within-structure, i.e. hierarchical morphologies, have recently attracted inter- est due to their potential use as functional materials. [1±3] Such materials have been demonstrated by combining block copolymer nanostructures with one order of magnitude smaller length-scale organization within one of the micro- phase separated domains, either using covalently bonded mesogenic moieties, [1,2,4,5] or using mesomorphic polymer/ amphiphile complexes [6,7] for one block. [3,8] Using polysty- rene-block-poly(4-vinylpyridine), i.e. PS-b-P4VP, hydrogen bonded to an oligomeric amphiphile, i.e. nonadecylphenol (NDP), we demonstrate that one can obtain lamellar-within- lamellar, lamellar-within-cylindrical, cylindrical-within-la- mellar, spherical-within-lamellar, and lamellar-within-sphe- rical morphologies in a straightforward way using supramo- lecular self-assembly. All of the structures are, for the first time, directly imaged using transmission electron micros- copy (TEM), thus revealing also their mutual orientation. Conventional AB diblock copolymers form highly orga- nized microphase separated structures in a series of well- known morphologies. [9] The characteristic length scale is given by the long period, which is usually within the 10± 100 nm range. On the other hand, organization at a much smaller length-scale can be achieved using liquid-crystalline (LC) polymers, complexation of mesogenic moieties to polymer backbones, [10±12] polyelectrolyte/surfactant complexes, [13±17] or hydrogen bonded polymer/amphiphile complexes. [6,18,19] These materials form organized nanostructures with a typi- cal length scale of 2±6 nm. Adv. Mater. 1999, 11, No. 9 Ó WILEY-VCH Verlag GmbH, D-69469 Weinheim,1999 0935-9648/99/0906-0777 $ 17.50+.50/0 777 Communications ± [*] Prof. O. Ikkala, J. Ruokolainen [+] Department of Engineering Physics and Mathematics Helsinki University of Technology PO Box 2200, FIN-02015 HUT, Espoo (Finland) Prof. G. ten Brinke Department of Polymer Science and Materials Science Center University of Groningen Nijenborgh 4, 9747 AG, Groningen (The Netherlands) [+] Also Institute of Biotechnology, Electron Microscopy, University of Helsinki, PO Box 56 FIN-00014 Helsinki, Finland. [**] Juha Tanner is acknowledged for experimental assistance. The work has been supported by Finnish Academy, Technology Development Center (Finland) and the Neste Foundation.