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Bicontinuous Cubic Mesoporous Materials with Biphasic Structures
Author(s) -
GarciaBennett Alfonso E.,
Xiao Changhong,
Zhou Chunfang,
Castle Toen,
Miyasaka Keiichi,
Terasaki Osamu
Publication year - 2011
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.201101831
Subject(s) - mesophase , transmission electron microscopy , crystallography , bar (unit) , materials science , mesoporous material , amphiphile , epitaxy , chemistry , liquid crystal , nanotechnology , copolymer , composite material , organic chemistry , physics , optoelectronics , polymer , layer (electronics) , meteorology , catalysis
The replication of amphiphilic systems within an inorganic silica matrix allows the study of the fundamental properties of mesostructural changes, that is, kinetic and structural parameters. Herein we report a detailed study of the transition between cubic bicontinuous mesostructure with space groups Ia $\bar 3$ d and Pn $\bar 3$ m symmetry, which are associated with the minimal G and D surfaces, respectively. The transition may be induced through micellar swelling of the anionic amphiphilic surfactant N ‐lauroyl alanine by trimethylbenzene. Rich kinetic behaviour is observed and has been exploited to prepare particles with biphasic structures. Transmission electron microscopy evidence indicates that there is epitaxial growth from one mesostructure to the other involving the [111] and [110] orientations of the Ia $\bar 3$ d and Pn $\bar 3$ m symmetry structures, respectively. From kinetic studies, we show that the formation of the Ia $\bar 3$ d mesophase is preceded by a hexagonal phase (plane group p 6 mm ) and an epitaxial relationship has been observed involving the sixfold or $\bar 3$ axis orientations of both structures. Our data suggests that the Pn $\bar 3$ m mesostructure is kinetically stable at low temperatures whereas the Ia $\bar 3$ d mesostructure is the more stable structure after prolonged periods of hydrothermal treatment. We present evidence from transmission electron microscopy and small‐angle X‐ray diffractograms and also electron crystallography modelling of the unit cells at particular points in the structural change.