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Covalent Connection of Individualized, Neutral, Dendronized Polymers on a Solid Substrate Using a Scanning Force Microscope
Author(s) -
AlHellani Rabie,
Barner Jörg,
Rabe Jürgen P.,
Schlüter A. Dieter
Publication year - 2006
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200600171
Subject(s) - dendrimer , covalent bond , polymer , materials science , substrate (aquarium) , chemistry , nanotechnology , polymer chemistry , organic chemistry , composite material , oceanography , geology
The synthesis of a neutral, high‐molar‐mass, acrylamide‐based, third‐generation dendronized polymer (denpol) with a defined number of azide groups at its periphery is reported. An attach‐to route is used in which a first‐generation denpol is reacted with second‐generation (G2) dendrons. The degree of structure perfection of the resulting denpol is quantified as 99.8 %. This value was obtained after the introduction of a fluorescence label at the sites that remained unaffected by the dendronization. The high coverage was independently confirmed for the dendronization of another first‐generation polymer and a closely related G2 dendron. The third‐generation denpol resulting from the first dendronization experiment was spin‐coated as a sub‐monolayer onto highly oriented graphite precoated with an ultrathin layer of C 12 H 25 NH 2 , which was introduced to provide a well‐defined substrate for denpol adsorption and manipulation. Scanning force microscopy revealed single denpols, which could be moved across the surface and “welded” by covalent cross‐linking induced by photochemical decomposition of the azides into highly reactive nitrenes. The successful formation of covalent bonds between two denpols was confirmed by mechanically challenging the link with the scanning force microscope (SFM) tip. This is the second reported case of a move–connect–prove sequence using polymers and the SFM, which for the first time employs noncharged denpols, thus widening the applicability of this method significantly.