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Carbosilane dendrimers with perfluoroalkyl end groups. Core-shell macromolecules with generation-dependent order

Lorenz, K. and Frey, H. and Stühn, B. and Mulhaupt, R. (1997):
Carbosilane dendrimers with perfluoroalkyl end groups. Core-shell macromolecules with generation-dependent order.
In: Macromolecules, pp. 6860-6868, 30, (22), [Article]

Abstract

A series of carbosilane dendrimer generations, G0 to G3, with 4, 12, 36, and 108 end groups, respectively, has been functionalized with perfluorohexyl (C6F13-) groups On the surface. Quantitative perfluoroalkylation of the dendrimer surface was achieved via free radical addition of 3,3,4,3,5,5,6,6,7,7,8,8,8-tridecafluoro-n-octyl mercaptan. Quantitative perfluoroalkylation of the dendrimers was demonstrated by NMR and SEC. The thermal properties of the dendrimers with core-shell structure were investigated by DSC, polarizing microscopy, and WAXS. Whereas GO was obtained as a crystalline material that did not show the formation of mesophases, G1 (12 end groups) exhibited the formation of a highly ordered smectic mesophase between -15 and -30 degrees C. In contrast, G2 and G3 did not form mesophases; however, a transition to a most probably hexagonally ordered array of columns could be observed. The generation-dependent thermal behavior is ascribed to the increasingly dense packing of perfluorohexyl groups on the dendrimer surface.

Item Type: Article
Erschienen: 1997
Creators: Lorenz, K. and Frey, H. and Stühn, B. and Mulhaupt, R.
Title: Carbosilane dendrimers with perfluoroalkyl end groups. Core-shell macromolecules with generation-dependent order
Language: English
Abstract:

A series of carbosilane dendrimer generations, G0 to G3, with 4, 12, 36, and 108 end groups, respectively, has been functionalized with perfluorohexyl (C6F13-) groups On the surface. Quantitative perfluoroalkylation of the dendrimer surface was achieved via free radical addition of 3,3,4,3,5,5,6,6,7,7,8,8,8-tridecafluoro-n-octyl mercaptan. Quantitative perfluoroalkylation of the dendrimers was demonstrated by NMR and SEC. The thermal properties of the dendrimers with core-shell structure were investigated by DSC, polarizing microscopy, and WAXS. Whereas GO was obtained as a crystalline material that did not show the formation of mesophases, G1 (12 end groups) exhibited the formation of a highly ordered smectic mesophase between -15 and -30 degrees C. In contrast, G2 and G3 did not form mesophases; however, a transition to a most probably hexagonally ordered array of columns could be observed. The generation-dependent thermal behavior is ascribed to the increasingly dense packing of perfluorohexyl groups on the dendrimer surface.

Journal or Publication Title: Macromolecules
Volume: 30
Number: 22
Divisions: 05 Department of Physics > Institute for condensed matter physics
05 Department of Physics
Date Deposited: 27 Feb 2010 12:31
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