Raspberry-Like Polysilsesquioxane Particles with Hollow-Spheres-on-Sphere Structure: Rational Design, Controllable Synthesis, and Catalytic Application

Abstract

Raspberry-like hollow-spheres-on-sphere (HSOS) particles with reactive surfaces, uniform sizes and monodisperse properties were rational designed and fabricated to immobilize gold nanoparticles for the catalytic reduction of 4-nitrophenol. HSOS polysilsesquioxane (PSQ) particles were constructed by an organic alkali catalyzed sol-gel process from trialkoxysilane precursors with stabilized polystyrene (PS) nanoparticles as both a sacrifice template and a Pickering emulsifier. The PSQ particles were fabricated in an ice bath with methyltrimethoxysilane and mercaptopropyltrimethoxysiane as a co-precursor, tetramethylammonium hydroxide (TMAH) as a catalyst, polyvinylpyrrolidone (PVP) and sodium lignosulfonat as co-stabilizers and PS latex as a hard template. The formation mechanism of the hierarchical particles was investigated in detail by the time study through imaging the particles at regular time intervals during the reaction process. Various effect factors on the morphology were studied systematically which showed that the precursor composition, the content of PS, TMAH and PVP are the most important factors. The hierarchical structure combined with the mercaptopropyl groups on both the surface and the skeleton to make it possible to adsorb guest molecules. Au nanoparticles were immobilized on the particles for the catalytic reduction of 4-nitrophenol to 4-aminophenol. The unique PSQ colloids with hollow-spheres-on-sphere extended the family of the hierarchical structures and has shown the potential applications in separations, drug delivery and heterogeneous catalysts.

Formation Mechanism of Monodispersed Polysilsesquioxane Spheres in One-Step Sol–Gel Method

“…Polysilsesquioxanes (PSQs), general formula (RSiO 1.5 ) n , are molecular-level organic–inorganic hybrid materials composed of siloxane (Si–O–Si) rigid backbones and evenly distributed functional groups. − PSQ spheres feature a wide range of potential applications in fields such as catalysis, − adsorption/separation, , biotechnology, , insulation materials, superhydrophobic materials, and so forth. PSQ spheres can be synthesized via various routes mainly including one-step and two-step sol–gel methods.…”

Hematite/Polystyrene Raspberry‐Like Microcomposites as Stable Support for Silver Nanoparticle Immobilization

“…[ 1 ] The unique properties of raspberry‐like composites including surface roughness, [ 2 ] surface heterogeneity, [ 3 ] and the presence of specific moieties [ 4 ] results in great number of their potential applications. Raspberry‐like composites are widely applied in catalysis, [ 5–8 ] plasmonics, [ 9–12 ] biology and medicine where they are introduced as platforms for immobilization of biomolecules, [ 13–15 ] in separation processes [ 16,17 ] and as hydrophobic coatings. [ 18–20 ]…”

Synthesis and Characterization of Unsymmetrical Double-Decker Siloxane (Basket Cage)

“…Many scientists have been interested in silsesquioxane cage materials with a well-defined structure because such materials have a low dielectric constant and excellent thermal stability [1,2,3,4,5,6,7]. Additionally, these compounds find a wide range of applications in polymers [8,9,10,11], sensors [12], catalysis [7,8,9,13], organic light-emitting diodes [14], host-guest complexes [15,16], and porous materials [17]. Most of the double-decker silsesquioxanes (DDSQ) [10,11,14,18,19,20,21,22,23,24,25,26] and polyhedral oligomeric silsesquioxanes [7,8,9,12,13,15,16,17,27,28,29] have a symmetrical structure with the same organic functional group on both sides.…”