Synergic Effects Of Imidazolium Ionic Liquids On P123Mixed Micelles For Inducing Micro/Mesoporous Materials

Ionic Liquids had notable synergic interaction with surfactant and formed surfactant/ILs aggregates with various composition and shape, when they were mixed with surfactant in the aqueous solution. ILs played an important role in adjusting the solution and interface properties because of their unique molecular structures and properties. Amphiphilic molecule assemblies are usually used as the soft-template for synthesizing porous materials. Various kinds of ILs/surfactant mixed micelles could be designed though choosing cations and anion of ILs, and consequently induce diverse porous materials.A series of micro/mesoporous silica composites were synthesized with Pluronic P123and imidazolium ILs ([Cnmim]X) as co-templates.[Cnmim]X had notable synergic interaction with P123. By changing the alkyl chain length n in methylimidazolium, ring-like micropores were observed on the wall of the mesoporous materials when n=4. While increasing n to10, micropores and mesopores were found in different separated regions. Material structures were decided by the different interaction between ILs and P123. With increasing the alkyl chain length n in methylimidazolium from4to10,[Cnmim]Br gradually exhibited properties of a surfactant, and hence P123/ILs mixed micelles showed various aggregation forms, which induced different pore structures.Various anions of Cl-, Br-and BF4-of ILs showed a little effect on the aggregation behavior of P123/C4X mixed micelles. Ordered micro/mesoporous silica composite was obtained with P123/C4C1as the co-template, similar with4Br-393. Different from Cl-and Br-the strong hydrogen bonding effect of BF4-resulted in larger ordered mesoporous channels and larger pore volume with numerous micropores in the wall at a low temperature of313K.The hydrophobic C4PF6only could be solubilized in the core of P123micelles, so that it swelled123micelles at low concentration, and resulted in the ordered hexagonal porous silica materials at313K. However, with increasing temperature or concentration, C4PF6greatly changed the hydrophobicity of both PEO and PPO blocks, and breaked P123micelles, consequently, the ordered structure gradually collapsed.