C₁₂mimBr Ionic Liquid/SDS Vesicle Formation and Use As Template for the Synthesis of Hollow Silica Spheres

Abstract

The phase behavior of an aqueous catanionic surfactant system, composed of a long-chain imidazolium ionic liquid 1-dodecyl-3-methylimidazolium bromide (C(12)mimBr) and sodium dodecyl sulfate (SDS), is described. The phase diagram of the catanionic system was determined by electrical conductivity measurements and the formation of vesicles in a birefringent L(alpha) phase characterized by transmission electron microscopy (TEM) and freeze-fracture transmission electron microscopy (FF-TEM). Rheological measurements were used to characterize the macroscopic properties of the birefringent L(alpha) phase. Both electrostatic and hydrophobic interactions contribute to the vesicle formation in the catanionic system. Compared to the DTAB/SDS aqueous solution, differences between the imidazolium and trimethylammonium headgroups geometric packing and charge density induce the different phase behavior in each system. Silica hollow spheres, with diameters 30-60 nm and a wall thickness of 8-10 nm, were prepared by using the vesicles as the templates. The hollow silica spheres were characterized by TEM, scanning electron microscopy (SEM), and nitrogen adsorption-desorption. The results suggest additional application for ionic liquid based vesicles to be used as templates for the synthesis of hollow inorganic materials.

Effect of hydrophilic ionic liquid on the micellar properties of aqueous Tween-20

“…The micelle formation of surfactants in ILs has been currently studied by many research groups [5][6][7][8][9][10][11][12][13][14][15][16]. The most frequently used ILs in this field are imidazolium salts with different anion species because of their widespread industrial use [5,9,12].…”

Hydrogen production by steam reforming of ethanol over dual-templated Ni–Al2O3 catalyst

“…Recently, ionic liquids have been used as templates to prepare microporous and mesoporous materials by taking advantage of their amphiphilic property [22]. Long chain ionic liquids, which are composed of ionic head and organic chain, have induced self-aggregation, demonstrating their potential usage as templates [23][24][25][26]. For example, C 16 mimCl has been used as a template to prepare monolithic supermicroporous silica with lamellar order via nanocasting technique [27,28].…”

Catanionic surfactant formation from the interaction of the cationic surfactant hexadecyltrimethylammonium bromide (CTAB) and the ionic liquid 1-butyl-3-methylimidazolium octyl sulfate (bmim-octyl SO4) in aqueous solution

“…In fact there are several examples of catanionic surfactants formed from ionic liquids. They can be obtained by synthesis combining the appropriate cation and anion [42][43][44][45][46][47] or by mixing the cationic and the anionic compounds in equimolar ratio in aqueous solution [48][49][50][51].…”