Functionalized Organosilica Microspheres via a Novel Emulsion-Based Route

Abstract

Thiol-functionalized organosilica microspheres were synthesized via a two-step process: (1) acid-catalyzed hydrolysis and condensation of 3-mercaptopropyltrimethoxysilane (MPTMS), followed by (2) base-catalyzed condensation, which led to the rapid formation of emulsion droplets with a narrow size distribution. These droplets continued to condense to form solid microspheres. Solution (29)Si NMR and optical microscopy were applied to study the mechanism of this novel synthetic route. Solid-state (29)Si NMR, SEM, zeta potential titration, and Coulter counter measurements were used to study the bulk and surface properties and to determine the particle size distributions of the final microspheres. Compared to conventional Stöber silica particles, these microspheres were shown to have a lower degree of cross-linking (average degree of condensation, r = 1.25), a larger average size (up to 6 microm), and a higher isoelectric point (pH = 4.4). Confocal microscopy of dye-labeled microspheres showed an even distribution of dye molecules throughout the interior, characteristic of a readily accessible and permeable organosilica network. These findings have implications for the production of functionalized solid supports for use in catalysis and biological applications, such as optically encoded carriers for combinatorial synthesis.

Functional role of cationic surfactant to control the nano size of silica powder

“…It can be used as effective materials in various cementitious system for improving the strength, flexibility, durability, workability, etc. Various synthetic strategies have been reported to prepare silica nanoparticles, such as the modified Stöber method (Grün et al 1999;Pauwels et al 2001;Liu et al 2003;Zhang et al 2004;Lebedev et al 2004;Tan et al 2004;Shimura et al 2005;Tan et al 2005), combustion techniques (Hong et al 2009), chemical vapor deposition (Awaji et al 1997), aerosol spray (Rao et al 2002;Bore et al 2003;Miller et al 2005),and emulsion (Oh et al 2005) method. Various types of morphology such as hexagonal, cubic, lamellar, and wormhole like mesostructures have been synthesized using these methods.…”

Refractometry of organosilica microspheres

“…Organosilica spheres were produced using a two-step process [2]. This process involved the hydrolysis and subsequent condensation of thiol-based silica precursor.…”

“…Since bulk properties of the material can vary as a result of nanotechnological synthesis, it is important to monitor them in situ. In particular, silica-derived novel material, termed organosilica, have been synthesized in the form of (nano/micro)spheres, with a range of useful qualities that have been reported [1,2]. Organosilica surface activation have appeared to be straightforward to bind oligonucleotide and peptide sequences for optical encoding and highthroughput screening via flow cytometry [1,2].…”

“…In particular, silica-derived novel material, termed organosilica, have been synthesized in the form of (nano/micro)spheres, with a range of useful qualities that have been reported [1,2]. Organosilica surface activation have appeared to be straightforward to bind oligonucleotide and peptide sequences for optical encoding and highthroughput screening via flow cytometry [1,2]. The optical encoding method, however, demands tight margins on organosilica microspheres size and refractive index to ensure reliable readout and correct interpretation of their scattering intensities in the context of flow cytometry.…”

Synthesis and Characterization of Cross-linked Polysiloxane Microspheres for Light-scattering

“…So the organic light diffusing agent has been developed, which mainly include PMMA and organic silicon microsphere. Polysiloxane microspheres' (PSQ) chemical formula is RSiO3/2, side group R is an organic group connected with silicon atoms, such as methyl, vinyl, phenyl, amino, mercapto, epoxy [3]. PSQ includes both inorganic silicone "skeleton" structure and also the ball's shape side groups of organic groups in the molecular structure.…”