title: Facile synthesis of size controllable dendritic mesoporous silica nanoparticles.
abstract: The synthesis of highly uniform mesoporous silica nanospheres (MSNs) with dendritic pore channels, particularly ones with particle sizes below 200 nm, is extremely difficult and remains a grand challenge. By a combined synthetic strategy using imidazolium ionic liquids (ILs) with different alkyl lengths as cosurfactants and Pluronic F127 nonionic surfactants as inhibitors of particle growth, the preparation of dendritic MSNs with controlled diameter between 40 and 300 nm was successfully realized. An investigation of dendritic MSNs using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen physisorption revealed that the synthesis of dendritic MSNs at larger size (100-300 nm) strongly depends on the alkyl lengths of cationic imidazolium ILs; while the average size of dendritic MSNs can be controlled within the range of 40-100 nm by varying the amount of Pluronic F127. The Au@MSNs can be used as a catalyst for the reduction of 4-nitrophenol by NaBH4 into 4-aminophenol and exhibit excellent catalytic performance. The present discovery of the extended synthesis conditions offers reproducible, facile, and large-scale synthesis of the monodisperse spherical MSNs with precise size control and, thus, has vast prospects for future applications of ultrafine mesostructured nanoparticle materials in catalysis and biomedicine.
authors.affiliation: Shanghai Key Laboratory of Green Chemistry and Chemical Processes, Department of Chemistry, East China Normal University , No. 3663 Zhongshan North Road, 200062 Shanghai, China.
authors.forename: Ye-Jun
authors.initials: YJ
authors.lastname: Yu
authors.forename: Jun-Ling
authors.initials: JL
authors.lastname: Xing
authors.forename: Jun-Ling
authors.initials: JL
authors.lastname: Pang
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Jiang
authors.forename: Koon-Fung
authors.initials: KF
authors.lastname: Lam
authors.forename: Tai-Qun
authors.initials: TQ
authors.lastname: Yang
authors.forename: Qing-Song
authors.initials: QS
authors.lastname: Xue
authors.forename: Kun
authors.initials: K
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Wu
mesh_terms: D003460:Crystallization / Q000379:methods*; D052578:Ionic Liquids / Q000737:chemistry*; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure*; D058608:Nanopores / Q000648:ultrastructure*; D010316:Particle Size; D020442:Poloxamer / Q000737:chemistry*; D016062:Porosity
chemical_list: D052578:Ionic Liquids; D020442:Poloxamer
keywords: alkyl imidazolium ionic liquids; colloidal mesoporous silica nanoparticles; growth inhibitor; size control