Title: Azobenzene-Derived Surfactants as Phototriggered Recycable Templates for the Synthesis of Ordered Mesoporous Silica Nanospheres

Author: Jing Wei, Yuyun Liu, Jia Chen, Yuhui Li, Qin Yue, Gaoxiang Pan, Yanlei Yu*, Yonghui Deng*, Dongyuan Zhao

Journal: Adv. Mater., 2014, 26(11), 1782-1787

Abstract：

An azobenzene-derived surfactant behaves as a “smart” molecule. Not only is it used as the structure-directing agent to synthesize unique mesoporous silica nanospheres, but it can also be quickly released from the silica framework with UV light and subsequently recycled.

Fulltext Link: https://onlinelibrary.wiley.com/doi/full/10.1002/adma.201305104

An azobenzene-derived cationic surfactant with photoresponsive properties is reported for using as a smart structure-directing agent in the synthesis of ordered MSNs. The surfactant confined in the silica matrix retains its photoresponsiveness and its tunable molecular size and polarity via cis–trans isomerism. After 1-h UV light irradiation, 80% of the surfactants in the silica framework can be released into mixed water/ethanol solvent and recycled from the solution. The recycled surfactant can be used again as the structure-directing agent in the templating synthesis of new MSNs. After removal of the AZTMA templates, the MSNs exhibit an open framework with accessible pores, radial mesopores, high surface area (~381 m2/g), uniform pore size (2.7 nm), and uniform diameter (~300 nm). The high surface area, unique mesoporous structure, and uniform spherical morphology of the MSNs makes them potential candidates for numerous applications such as adsorption, catalysis, and drug delivery.