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Self‐Assembly of Alkyl‐Substituted Cubic Siloxane Cages into Ordered Hybrid Materials
Author(s) -
Shimojima Atsushi,
Goto Ryota,
Atsumi Norimasa,
Kuroda Kazuyuki
Publication year - 2008
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.200801106
Subject(s) - siloxane , alkyl , materials science , lamellar structure , alkoxy group , calcination , self assembly , amphiphile , nanoporous , silanes , hybrid material , chemical engineering , crystallography , polymer chemistry , organic chemistry , copolymer , chemistry , silane , nanotechnology , catalysis , composite material , polymer , engineering
Siloxane‐organic hybrids with well‐ordered mesostructures were synthesized through the self‐assembly of novel amphiphilic molecules that consist of cubic siloxane heads and hydrophobic alkyl tails. The monoalkyl precursors functionalized with ethoxy groups (C n H 2 n +1 Si 8 O 12 (OEt) 7 , 1 C n , n =16, 18, and 20) were hydrolyzed under acidic conditions with the retention of the siloxane cages, leading to the formation of two‐dimensional hexagonal phases by evaporation‐induced self‐assembly processes. Analysis of the solid‐state 29 Si MAS NMR spectra of these hybrid mesostructures confirmed that the cubic siloxane units were cross‐linked to form siloxane networks. Calcination of these hybrids gave mesoporous silica, the pore diameter of which varied depending on the alkyl‐chain length. We also found that the precursors that had two alkyl chains formed lamellar phases, thus confirming that the number of alkyl chains per cage had a strong influence on the mesostructures. These results expand the design possibility of novel nanohybrid and nanoporous materials through the self‐assembly of well‐defined oligosiloxane‐based precursors.