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Tunable Gel Formation by Both Sonication and Thermal Processing in a Cholesterol‐Based Self‐Assembly System
Author(s) -
Wu Junchen,
Yi Tao,
Xia Qian,
Zou Ying,
Liu Feng,
Dong Jie,
Shu Tianmin,
Li Fuyou,
Huang Chunhui
Publication year - 2009
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.200900409
Subject(s) - sonication , alkyl , nucleation , chemical engineering , materials science , scanning electron microscope , transmission electron microscopy , dynamic light scattering , intermolecular force , self assembly , chemistry , nanotechnology , organic chemistry , nanoparticle , chromatography , molecule , composite material , engineering
Sonication‐induced gelation : Adaptive gels that are responsive to ultrasound were prepared and characterized. The self‐assembly of the gelators can be controlled by ultrasound (S‐gel) stimuli and renewed by a thermodynamic process (T‐gel, see images).A family of asymmetric cholesterol‐based fluorescent organogelators containing naphthalimide, connected by two acylamines and different alkyl‐chain spacers, have been designed and prepared. These compounds can gelate a variety of organic solvents with both ultrasound stimuli and general sol–gel processes. The self‐assembly and gelling properties of the compounds depend on the length of the alkyl chains and can be controlled by ultrasound stimuli and renewed by a thermodynamic process. The morphologies and surface wetabilities of the xerogels prepared from these gelators are strongly affected by environmental stimuli. The mechanism of the process was investigated by confocal laser scanning microscopy, transmission or scanning electron microscopy, wide‐angle X‐ray scattering analysis, and rheological experiments. The studies reveal that the cooperation and relative competition of multiple intermolecular interactions, influenced by the sonication or thermal stimulus, are the main contributors for the aggregation or nucleation processes; this results in the macrodifferences in morphology and surface properties. These results provide a deeper understanding of the intermediate transition state of the gel during use of an ultrasound stimulus.