Study of the texture of monodisperse silica sphere samples in the nanometer size range

Lecloux, A. J.; Bronckart, Joseph; Noville, Francis; Dodet, Claude; Marchot, Pierre; Pirard, Jean‐Paul

doi:10.1016/0166-6622(86)80289-x

Cited by 30 publications

(27 citation statements)

References 9 publications

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“…[13] Interestingly, the organosilica core particles have an increased porosity and, as a consequence, a decreased particle density of 1.51 g/mL in contrast to pure TES particles (r = 1.98 g/mL). However, also pure TES particles are not densely crosslinked systems but contain nanosized pores, as has been shown previously via nitrogen adsorption±desorption studies by Lecloux et al [14] Using APS as a silane coupling agent for fluorescein or rhodamine isothiocyanate (FITC, RITC), van Blaaderen et al have been able to prepare well-defined fluorescent core±shell particles useful for optical studies in colloidal physics. [15,16] To obtain tracers for measurements of the single particle mobility by fluorescence recovery after photobleaching (FRAP [10,11] ), a silica core with radius of about 150 nm was coated with a thin shell of FITC±APS.…”

Section: Silica Particles With Incorporated Fluorescent Dyesmentioning

confidence: 87%

“…Preliminary DLS experiments are reported by LizMarzan and Philipse that demonstrate the suitability of their new tracer system for optical studies. [23] The porosity of the silica shell [13,14] has been nicely demonstrated by Liz-Marzan for silica-coated silver clusters. [20] Here, the core±shell particles have been prepared in a similar way to the gold particles, i.e., using APS as a silane coupling agent, with a slight modification concerning the shell growth: after formation of a thin stabilizing layer by deposition of active silica, the particles are not transferred to EtOH in order to continue the shell growth by the Stöber mechanism, but EtOH is added to the dispersion.…”

Section: Silica-coated Metal Clustersmentioning

confidence: 99%

“…Due to incomplete conversion, however, these particles in practice are not perfectly crosslinked but rather contain nanosized pores. [13,14] Further, functional trimethoxysilanes can be used as comonomers to introduce, for example, fluorescent dye molecules into Stöber particles. [15,16] Therefore, the pure silica system is topologically not that different from the trimethoxysilane microgel system recently established in our group, i.e.…”

Section: Introductionmentioning

confidence: 99%

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Crosslinked Spherical Nanoparticles with Core-Shell Topology

2000

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Core–shell microgels are crosslinked nanosized spherical particles with a chemical composition that is different on the surface compared to the core region. By employing a core with special optical properties, e.g., a core labeled either with organic dye molecules or noble metal clusters (see Figure), these particles are perfectly suited as optical tracers in diffusion measurements. Here, the shell may be important for several reasons: (i) as a protective coating to suppress any influence of the labels on particle mobility, (ii) to optically separate individual particles even at high concentrations, and (iii) to compatibilize the particles with e.g., polymeric chains. Recent developments in the field of crosslinked core–shell particles are reviewed here, with a focus on such optical tracer systems.

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Section: Silica Particles With Incorporated Fluorescent Dyesmentioning

confidence: 87%

Section: Silica-coated Metal Clustersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Crosslinked Spherical Nanoparticles with Core-Shell Topology

2000

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“…1, it was argued in the paper of Lecloux et al (39) that the high value of SBET compared to So, as was measured and calculated by them for particles similar to A6, is due to the presence of micropores. They based this conclusion on the agreement they found between the cumulative specific surface area S,,,, without a correction for the micropores, and the calculated So.…”

Section: B Specijic Surface Area and Porositymentioning

confidence: 99%

“…Because the particles investigated are relatively large, AND VRIJ the pore volume attributed to these internal micropores is creasing particle radius ( 39 ) . The finding of micropores in small.…”

Section: B Specijic Surface Area and Porositymentioning

confidence: 99%

Synthesis and Characterization of Monodisperse Colloidal Organo-silica Spheres

Blaaderen

Vrij

1993

Journal of Colloid and Interface Science

409

345

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Monodisperse, colloidal silica spheres were prepared from tetraethoxysilane (TES) in mixtures of ammonia, water, and ethanol. The surface of the particles could be coated through a subsequent chemical reaction with the silane coupling agent 3-aminopropyltriethoxysilane (APS). Also, a new kind of monodisperse, colloidal silica spheres (organo-silica spheres) was prepared starting from mixtures of APS and TES. Organo-silica spheres synthesized with equal amounts of APS and TES were found to contain as much as 37% of the total amount of APS. The amount taken up by the particles, and therefore also the particle properties, depended on the initial composition of the mixture of alkoxides. It is argued that the most important reaction by which APS is incorporated into the particles is through an alcohol-producing condensation reaction with a silanol group bonded to a silicon atom that was part of a TES molecule. Because of this proposed mechanism, it is argued that this basecatalyzed method of making hybrid organic-silica particles will also be applicable to mixtures of other organoalkoxides. The organo-silica spheres differed from silica spheres prepared with TES alone in the following aspects: The negative surface charge in the mixture of water, ammonia and ethanol was reduced, the mass density was lower (e.g., 1.51 g/cm3 compared to 1.98 g/cm3), the microporosity was larger, and the siloxane structure was less condensed. The particle refractive index was higher, but the differences were small (around 0.02). It was shown that particles with APS on the surface could be grown larger with a silica layer prepared from TES. Organo-silica particles and silicacoated organo-silica particles were surface coated with stearyl alcohol. The resulting stability in several solvents was assessed. The different colloidal systems were characterized by static and dynamic light scattering, transmission electron microscopy, elemental analysis, nitrogen adsorption measurements, electrophoresis, and qualitative r3C and quantitative r9Si solid-state nuclear magnetic resonance spectroscopy. 8

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Optical Nanosphere Sensor Based on Shell‐By‐Shell Fabrication for Removal of Toxic Metals from Human Blood

El‐Safty

Abdellatef

Ismael

et al. 2013

Adv Healthcare Materials

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Because toxic heavy metals tend to bioaccumulate, they represent a substantial human health hazard. Various methods are used to identify and quantify toxic metals in biological tissues and environment fluids, but a simple, rapid, and inexpensive system has yet to be developed. To reduce the necessity for instrument-dependent analysis, we developed a single, pH-dependent, nanosphere (NS) sensor for naked-eye detection and removal of toxic metal ions from drinking water and physiological systems (i.e., blood). The design platform for the optical NS sensor is composed of double mesoporous core-shell silica NSs fabricated by one-pot, template-guided synthesis with anionic surfactant. The dense shell-by-shell NS construction generated a unique hierarchical NS sensor with a hollow cage interior to enable accessibility for continuous monitoring of several different toxic metal ions and efficient multi-ion sensing and removal capabilities with respect to reversibility, longevity, selectivity, and signal stability. Here, we examined the application of the NS sensor for the removal of toxic metals (e.g., lead ions from a physiological system, such as human blood). The findings show that this sensor design has potential for the rapid screening of blood lead levels so that the effects of lead toxicity can be avoided.

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Study of the texture of monodisperse silica sphere samples in the nanometer size range

Cited by 30 publications

References 9 publications

Crosslinked Spherical Nanoparticles with Core-Shell Topology

Crosslinked Spherical Nanoparticles with Core-Shell Topology

Synthesis and Characterization of Monodisperse Colloidal Organo-silica Spheres

Optical Nanosphere Sensor Based on Shell‐By‐Shell Fabrication for Removal of Toxic Metals from Human Blood

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