Organic−Inorganic Hybrid Hollow Nanospheres with Microwindows on the Shell

Abstract

We demonstrate, for the first time, that organic−inorganic hybrid hollow nanospheres with controllable size (12−20 nm) and shell thickness (4−7 nm) can be successfully synthesized through the condensation of 1,2-bis(trimethoxysilyl)ethane (BTME) around an inorganic-electrolyte-stabilized F127 micelle under a mild buffer condition (NaH2PO4−Na2HPO4, pH ∼7.0). The hollow spheres feature microwindows with pore size about 0.5−1.2 nm on the shell, which allow the guest molecules to diffuse into the hollow cavities. It was found that the concentration of the buffer solution in the synthesis was crucial to the formation of hollow nanosphere. At a low buffer concentration (20−100 mM), the surfactant exists as individual micelle. A core/shell nanocomposite was formed by the deposition of BTME at the corona of individual micelle, which leads to the formation of organic−inorganic hybrid nanoparticles with hollow interior after the extraction of the surfactant. The aggregation of individual micelles was observed at higher buffer concentration (>200 mM), which favors the formation of irregularly shaped particles with ordered mesostructure. This work presents a novel and facile strategy to fabricate hollow nanospheres with microwindows, which provides a versatile platform for practical applications of organic−inorganic hybrid materials in a broad range of fields such as catalysis, encapsulation, and drug delivery, etc.

An acid-free route for the facile synthesis of iron-functionalized mesoporous silicas: Transformation between hollow nanospheres and cage-like mesostructures

“…3A and B, respectively. Two capillary condensation steps (the first is from the interior core, and the second is from the interparticle void space) are present in all these isotherms, which is similar to the N 2 sorption isotherms of previously reported hollow nanospheres [20,43]. The core diameters of the hollow nanospheres are in the range of 11.3 and 8.8 nm for Fe-NS-0.8 and Fe-NS-1.5, respectively (Table 1), which are consistent to those estimated from TEM.…”

“…3C. The micropores are likely originated from the shell of the hollow nanospheres, which are randomly interconnected to reach the inner cavity [20,43]. The above characterizations suggest that the Fe-substituted hollow nanospheres have been successfully synthesized in the neutral reaction medium.…”

“…Among the silica fibers, spheres, rods and nanoparticles, the hollow nanospheres are very attractive, given that the hollow interior can encapsulate the guest molecules for wide application potentials [19][20][21][22][23][24][25][26][27][28]. The modification of the shell of the hollow nanospheres may further expand the application potentials of the hollow nanospheres [29][30][31][32][33][34][35].…”

Mesoporous Silica Nanoparticles: A Review

“…Single micelle-templating: Yang et al synthesized small hollow organosilica nanotubes and nano-spheres by using sufficient amount of organosilica as a precursor and Pluronic triblock copolymer with the different hydrophobicity [90,91]. Mandal and Kruk produced HSNs of varying size by using Pluronic F127 block copolymer template synthesis of ethylene-bridged organosilicas in the presence of swelling agent [92].…”

Morphology control of silica/poly(methyl methacrylate-co-styrene) hybrid nanoparticles via multiple-miniemulsion approach

“…As a solution, one can force polymer and inorganic phases to interact at a molecular level and upscale the physical properties of the ultimate composite material (7,8). A standard technique for hybrid organic-inorganic material formation uses either hollow particles (9)(10)(11) or capsules (12,13). Due to their ability to encapsulate versatile functional cargos; these methods gained wide applications in catalysis (14), drug-delivery systems (15,16), biology (17), coatings (18,19), and so on.…”