Interplay between H-Bonding and Alkyl-Chain Ordering in Self-Assembly of Monodendritic L-Alanine Derivatives

Authors

  • Dr. Denis V. Anokhin ,

    1. Institut de Sciences des Matériaux de Mulhouse (CNRS IS2M), 15 rue Jean Starcky, 68057 Mulhouse (France), Fax: (+33) 389608799
    2. Moscow State University, Faculty of Fundamental Physical and Chemical Engineering, 119991, Moscow, GSP-1, 1-51 Leninskie Gory (Russia)
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  • Dr. Jānis Lejnieks,

    1. DWI an der RWTH Aachen e.V. und Institut für Technische und Makromolekulare Chemie der RWTH Aachen, Pauwelsstr. 8, 52056 Aachen (Germany), Fax: (+49) 241-8023301
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  • Dr. Ahmed Mourran,

    Corresponding author
    1. DWI an der RWTH Aachen e.V. und Institut für Technische und Makromolekulare Chemie der RWTH Aachen, Pauwelsstr. 8, 52056 Aachen (Germany), Fax: (+49) 241-8023301
    • DWI an der RWTH Aachen e.V. und Institut für Technische und Makromolekulare Chemie der RWTH Aachen, Pauwelsstr. 8, 52056 Aachen (Germany), Fax: (+49) 241-8023301
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  • Dr. Xiaomin Zhu,

    1. DWI an der RWTH Aachen e.V. und Institut für Technische und Makromolekulare Chemie der RWTH Aachen, Pauwelsstr. 8, 52056 Aachen (Germany), Fax: (+49) 241-8023301
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  • Dr. Helmut Keul,

    1. DWI an der RWTH Aachen e.V. und Institut für Technische und Makromolekulare Chemie der RWTH Aachen, Pauwelsstr. 8, 52056 Aachen (Germany), Fax: (+49) 241-8023301
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  • Prof. Martin Möller,

    1. DWI an der RWTH Aachen e.V. und Institut für Technische und Makromolekulare Chemie der RWTH Aachen, Pauwelsstr. 8, 52056 Aachen (Germany), Fax: (+49) 241-8023301
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  • Dr. Oleg Konovalov,

    1. European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz, 38043 Grenoble (France)
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  • Dr. Natalia Erina,

    1. Bruker Nano-Surface Inc. (formerly Veeco Metrology Instruments), 112 Robin Hill Road, Santa-Barbara, CA 93110 (USA)
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  • Dr. Dimitri A. Ivanov

    Corresponding author
    1. Institut de Sciences des Matériaux de Mulhouse (CNRS IS2M), 15 rue Jean Starcky, 68057 Mulhouse (France), Fax: (+33) 389608799
    • Institut de Sciences des Matériaux de Mulhouse (CNRS IS2M), 15 rue Jean Starcky, 68057 Mulhouse (France), Fax: (+33) 389608799
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Abstract

This paper reports on the synthesis and self-organizing properties of monodendrons consisting of L-alanine at the focal point and alkyl chains with different length at the periphery. The structures of thin films and monolayers are studied by temperature-resolved grazing-incidence X-ray diffraction and scanning force microscopy. The interplay between H-bonding and ordering of the alkyl chains results in a rich temperature-dependent phase behavior. The monodendrons form H-bonded stabilized clusters with the number of molecules depending on the length of the aliphatic chains and temperature. The clusters play the role of constitutive units in the subsequent self-assembly. Short alkyl chains allow the material to form thermodynamically stable crystalline phases. The molecules with longer side groups exhibit additional transitions from the crystalline phase to thermotropic columnar hexagonal or columnar rectangular liquid-crystalline phases. In monolayers deposited on highly ordered pyrolytic graphite, the materials show ordering similar to thin films. However, for the compound bearing hexadecyl chains the affinity of the alkyl groups to graphite dominates the self-assembly and thereby allows epitaxial growth of a 2D lattice with flat-on oriented molecules.

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