Structure transition from hexagonal mesostructured rodlike silica to multilamellar vesicles

Yuan, Pei, Yang, Sui, Wang, Hongning, Yu, Meihua, Zhou, Xufeng, Lu, Gaoqing, Zou, Jin and Yu, Chengzhong (2008) Structure transition from hexagonal mesostructured rodlike silica to multilamellar vesicles. Langmuir, 24 9: 5038-5043. doi:10.1021/la8000569

Author Yuan, Pei
Yang, Sui
Wang, Hongning
Yu, Meihua
Zhou, Xufeng
Lu, Gaoqing
Zou, Jin
Yu, Chengzhong
Title Structure transition from hexagonal mesostructured rodlike silica to multilamellar vesicles
Journal name Langmuir   Check publisher's open access policy
ISSN 0743-7463
Publication date 2008-05-06
Year available 2008
Sub-type Article (original research)
DOI 10.1021/la8000569
Open Access Status Not yet assessed
Volume 24
Issue 9
Start page 5038
End page 5043
Total pages 6
Place of publication Washington , D.C.
Publisher American Chemical Society
Language eng
Subject C1
970102 Expanding Knowledge in the Physical Sciences
100708 Nanomaterials
Abstract We studied the synthesis of siliceous structures by using a nonionic block copolymer (Pluronic P123) and perfluorooctanoic acid (PFOA) as cotemplates in an acid-catalyzed sol-gel process. Different siliceous structures were obtained through systematically varying the molar ratio (R) of PFOA/P123, and the resultant materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen sorption analysis, and Fourier-transform infrared spectroscopy. The results are consistent and reveal a structure transition from a highly ordered 2D hexagonal (HEX) mesostructure with a rodlike morphology to multilamellar vesicles (MLVs) with sharp edges when R is increased. The fact that the MLVs are initiated from the end of hexagonally mesostructured rods provides key evidence in such a novel structure transition. Our finding indicates that, at least in our observations, the MLVs are developed gradually from HEX structures, rather than by a direct cooperative self-assembly mechanism. It is suggested that PFOA molecules with rigid fluorocarbon chains closely interact with PEO. This interaction model may well explain (1) the "wall-thicken" effect in HEX mesostructures by enlarging the hydrophilic PEO moiety (R = 0-1.4), (2) the subsequent HEX to multilamellar structure transition by modifying the hydrophilic/hydrophobic volume ratio (R = 1.4-2.8), and (3) the formation of MLVs with sharp edges by increasing the bending energy. This model provides insight into the fabrication of novel porous materials by the use of block copolymers and fluorinated surfactant mixed templates.
Keyword Ordered Mesoporous Silica
Hydrocarbon Surfactant Mixtures
Poly (Ethylene Glycol) Oligomers
Hollow Spheres
Morphological Control
Cationic Surfactant
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: 2009 Higher Education Research Data Collection
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Citation counts: TR Web of Science Citation Count  Cited 24 times in Thomson Reuters Web of Science Article | Citations
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Created: Fri, 20 Mar 2009, 22:16:11 EST by Sally Beard on behalf of Materials