Two-Dimensional Structure of Self-Assembled Alkyl-Substituted Polyphenylene Dendrimers on Graphite

Autor:	Simona Loi, Hans-Jürgen Butt, Roland E. Bauer, Christina Hampel, Klaus Müllen, Uwe-Martin Wiesler
Rok vydání:	2002
Předmět:	chemistry.chemical_classification Materials science Surfaces and Interfaces Condensed Matter Physics Crystallography chemistry Phase (matter) Dendrimer Monolayer Electrochemistry Organic chemistry General Materials Science Nanorod Self-assembly Graphite Spectroscopy Alkyl Macromolecule
Zdroj:	Langmuir. 18:2398-2405
ISSN:	1520-5827 0743-7463
DOI:	10.1021/la0114326
Popis:	Three types of polyphenylene dendrimers were demonstrated to spontaneously form stable, pinhole-free monolayers on graphite with a complex two-dimensional structure (Loi et al. Macromolecules 2001, 34, 3661). For this paper, we extended our study using four new dendrimers to draw more general conclusions. Monolayers were prepared by spin-coating and analyzed by atomic force microscopy. The dendrimers consist of a core of twisted, interlocked benzene rings and an external shell of alkyl chains. All structures observed can be divided into three types which can coexist on one sample: (1) granular regions, where individual dendrimers could be identified in a glasslike phase, (2) diffuse, homogeneous regions, and (3) nanorod regions consisting of parallel rows of 5.1−5.9 nm spacing. Dendrimers with alkyl chains of different lengths showed the same spacing between nanorods. This indicates that the alkyl chains are oriented parallel to the direction of the nanorods. In addition, some dendrimers form two-dimensi...
Databáze:	OpenAIRE
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