Periodic Mesoporous Organosilicas from Polyion Complex Micelles – Effect of Organic Bridge on Nanostructure

Abstract

A new family of polyion complex (PIC)-based periodic mesoporous organosilicas, PICPMOs, obtained by the hydrolysis-condensation of organosilanes containing organic bridging units (phenylene, ethenylene and ethylene) in the presence of polyion complex (PIC) micelles as structure-directing agents (SDAs), is described. The electrostatic interactions between the acrylic acid functions of a poly(ethylene oxide)-bpoly(acrylic acid) double-hydrophilic block copolymer (DHBC) and the primary amine functions of a polyamine micellization agent control the formation of the core of the micellar complex, while the PEO chains of the micelle corona mediate the formation of the organic/inorganic interface that controls the evolution of the material. Herein, the micellization agent employed [a]

Single-template periodic mesoporous organosilica with organized bimodal mesoporosity

“…PMOs with high surface areas and uniform porosity are typically obtained via the hydrolysispolycondensation of organosilanes with general stoichiometry (R'O)3Si-R-Si(OR')3 using appropriate SDAs. The organic functions (R) in the precursor are covalently bridged between two Si atoms, which ensures their regular distribution within the pore walls of the PMOs [31], while the range of potential bridging groups enables a correspondingly wide variety of functionalities to be introduced into the mesoporous hybrids [24,32,33].…”

Oxidation-Sensitive Supramolecular Polymer Nanocylinders

“…The latter ones protect the one-dimensional structures from lateral aggregation, resulting in isolated nanocylinders in solution. The anisotropic character of isolated polymer nanocylinders makes them relevant for various applications: − drug delivery, , synthesis of mesoporous inorganic materials, catalysis, organic electronics, or emulsion stabilization . Imparting stimuli-responsiveness to supramolecular nanocylinders may allow their disassembly after use, which can be critical to reaching reversibly controlled systems.…”

Dual control of external surface and internal pore structure of small ordered mesoporous silica particles directed by mixed polyion complex micelles

“…It originates from a hydrogen bonding interaction between silicic species (Si) and ether oxygen of the neutral PEO block of a double hydrophilic block copolymer (DHBC) with a weak polyacid as a second block. The polyacid block, usually poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMAA), is meanwhile involved in the electrostatic complexation of a weak polyamine, such as oligochitosan (OC), [29,30] poly-L-lysine [31][32][33] or aminoglycoside antibiotics, [34][35][36] forming an organic complex coacervate core which then produces the mesoporous network after calcination of the material. Various topologies (cylindrical hexagonal, lamellar, wormlike) of the PIC-templated mesostructured materials (hereafter referred to as the mesoPIC family of materials) were obtained by simultaneously controlling the relative extents of hydrogen bonding interaction of the silicic species with the EO units, the electrostatic complexation of the polyions between the carboxylate (AA) and amine (N) groups, and the silica condensation rate.…”