Transformation of Mesostructured Silica Nanoparticles into Colloidal Hollow Nanoparticles in the Presence of a Bridged-Organosiloxane Shell

Abstract

Hollow siloxane-based nanoparticles (HSNs) have attracted significant attention because of their unique properties and applications. Recently, it was discovered that the simple covering of silica nanoparticles with an organosiloxane shell leads to the spontaneous formation of HSNs; however, the detailed mechanism of their formation has not yet been established. In this study, colloidal 30 nm HSNs were prepared by adding organically bridged alkoxysilane to an aqueous dispersion of mesostructured silica–surfactant composite nanoparticles, and the temporal changes of the morphology and chemical state of the nanoparticles were monitored to elucidate the formation mechanism. Core silica was dissolved after the formation of the core–shell structured nanoparticles, and almost all the dissolved silicate species were incorporated in the organosiloxane shell, changing the shell thickness. Two conditions were essential for silica dissolution induced by covering with organosiloxane: (i) presence of a sufficient amount of uncondensed Si–OH groups in the organosiloxane shell, and (ii) elevated temperature and pH for the promotion of the hydrolysis of silica. These findings will enable the fabrication of various HSNs through organosiloxane-induced silica dissolution and redeposition.

Mesoporous Organosilica Hollow Nanoparticles: Synthesis and Applications

“…In order to generalize the process and to control the hollow structures, Kuroda and co‐workers have systemically investigated the mechanism for the transformation of SiO 2 hard cores into HPMO nanospheres via the deposition of a organosilica shell . They have demonstrated that the soluble silicates of the SiO 2 hard‐core suspensions slightly decreased after the structural transformation.…”

Electron Tomography: A Unique Tool Solving Intricate Hollow Nanostructures

“…[58][59][60] In particular, the control over surfactant/silica assembly realizes the construction of various types of porous structures, which have been well studied via ET. [58][59][60] In particular, the control over surfactant/silica assembly realizes the construction of various types of porous structures, which have been well studied via ET.…”

“…Compared to carbon hollow spheres, silica nanoparticles have been engineered with more complicated structures due to the ease of structure tailoring via various synthesis strategies. [58][59][60] In particular, the control over surfactant/silica assembly realizes the construction of various types of porous structures, which have been well studied via ET. [61][62][63] The hollow intervals are typically distinguished by the highcontrast edge of silica shell using conventional TEM.…”

Noncovalent Immobilization of Yarrowia lipolytica Lipase on Dendritic-Like Amino Acid-Functionalized Silica Nanoparticles

“…For instance, immobilizing enzymes on silica needs this hybridization. However, many methods of enzyme immobilization rely on cross-linking and covalent immobilization [19]. In most cases, these methods deal with drawbacks such as inactivation of the enzyme by occupying the active sites of the enzyme and affecting the rotational mobility [20] or increasing the steps of preparation which make the process unsuitable for an efficient (photo)(bio)catalytic process.…”