Synthesis of Inorganic and Organic–Inorganic Hybrid Hollow Particles Using a Cationic Surfactant with a Partially Fluorinated Tail

Abstract

A new partially fluorinated cationic surfactant, 1‐(10‐perfluorooctyldecyl)pyridinium bromide monohydrate, is synthesized and used as the template for mesoporous ceramic and inorganic–organic hybrid particles. Several hydrolyzed alkoxide precursors are shown to co‐assemble with this surfactant to form hollow vesicle‐like particles, and the effect of changing the alkoxide chemical structure on the formation of these particles is examined. Tetramethoxysilane produces cubic or columnar particles without hollow cavities, but all other tetra‐n‐alkoxysilanes tested up to the n‐butoxide produce hollow particles. As the alkoxide length increases, the shell structure changes from multilayered (with Si(OC2H5)4) to a single thin layer (with Si(OC3H7)4) to a single thick layer (with Si(OC4H9)4). The stability of the fluorocarbon bilayers allows similar vesicular structures to be obtained in organic–inorganic hybrids prepared with bridged alkoxysilanes. Ethylene‐bridged silanes display similar structures to tetraalkoxysilanes. However, the hollow structures appear to partially collapse when the bridging chain is too long (octylene) and no hollow particles are formed with bis(trialkoxysilylpropyl)amines.

Recent Progress on Silica Coating of Nanoparticles and Related Nanomaterials

“…Their importance lies in the stability and extreme hydrophobicity of the fluorocarbon core of the aggregates, which allows the use of organically modified silane precursors in water (e.g., ethylene-bridged precursors). Different surfactants that were successfully employed for the synthesis of (solid and hollow) silica particles include perfluorodecylpyridinium derivatives, [83,84] and quaternary ammoniumbased fluorosurfactants. [85] These last amphiphiles, in combination with CTAB, have also been extended toward the preparation of periodic, mesoporous organosilica hollow spheres with tunable wall thickness, through a dual vesicle-liquid crystal templating approach.…”

Fabrication of high specificity hollow mesoporous silica nanoparticles assisted by Eudragit for targeted drug delivery

“…Soft-templating, including emulsion systems [12][13][14] and vesicle-templating [15][16][17], is a simple fabrication process [11]. However, due to the complex effects of physicochemical parameters in synthesis reactions and the high sensitivity of the soft templates to the reaction conditions, HMSNs prepared via this route are always observed with a broad size distribution [18] and a poor suspensibility and dispersity [11], which in turn, limits their biomedical applications.…”

Tunable Assembly of Organosilica Hollow Nanospheres

“…The fabrication of organosilicas in nanospherical morphology has attracted much research attention because of their potential applications in catalysis, drug delivery, and protection materials for biomolecules. [5][6][7][8][9][10][11] Due to the difficulty in the synthesis of hollow nanospheres, there are only limited reports for the synthesis of OHNs. [5][6][7][8][9][10][11] The first OHNs (particle size in the range 300-800 nm) with ethylene-bridging group and highly ordered mesoporous structure in the shell were reported by Lu's group through a vesicle and a liquid crystal "dual templating" approach.…”

“…[5][6][7][8][9][10][11] Due to the difficulty in the synthesis of hollow nanospheres, there are only limited reports for the synthesis of OHNs. [5][6][7][8][9][10][11] The first OHNs (particle size in the range 300-800 nm) with ethylene-bridging group and highly ordered mesoporous structure in the shell were reported by Lu's group through a vesicle and a liquid crystal "dual templating" approach. 5 Recently, the ethane-silica hollow nanospheres were facilely synthesized through condensation of 1,2-bis(trimethoxysilyl)ethane (BTME) around an inorganic-electrolyte-stabilized F127 micelle under mild buffer conditions (NaH 2 PO 4 -Na 2 HPO 4 , pH ≈ 7.0).…”

“…6 Multilamellar vesicles, ethane-silica hollow nanoparticles, were also synthesized using a cationic surfactant with a partially fluorinated tail. 7 The same method was extended for the synthesis of organosilica hollow particles using a silane precursor with a long bridging chain, such as bis(triethoxysilyl)octane, but only a limited number of particles have hollow spherical morphology. 7 Yu and co-workers reported the synthesis of multilamellar vesicles through a single-templating approach by using Pluronic P85 (EO 26 PO 39 EO 26 ) as a structure directing agent and 1,2-bis(triethoxysilyl)ethane as an organosilica source under mild conditions (pH 5.5).…”