Particle Size Distribution Inferred from Small-Angle X-ray Scattering and Transmission Electron Microscopy

Rieker, T. P.; Hanprasopwattana, A.; Datye, Abhaya K.; Hubbard, Paul F.

doi:10.1021/la9810713

Cited by 80 publications

(64 citation statements)

References 5 publications

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“…At high q (length scales below 10 nm), the data show a q −4 power law which can be interpreted as the Porod regime of the smooth surface, 3d silica monomers. A weak ripple observed in the Porod regime could be due to a narrow size distribution for monomers (Rieker et al 1999). The TEM pictures (Figure 3) showing a uniform monomer size distribution support this observation.…”

Section: Morphology Of the Silica Aggregatessupporting

confidence: 58%

Synthesis of Silica Aerosol Gels via Controlled Detonation

Dhaubhadel

Rieker

Chakrabarti

et al. 2012

Aerosol Science and Technology

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Silica (SiO 2 ) aerosol gels were formed via Brownian aggregation of silica nanoparticles in a closed reaction chamber. A sudden and quick detonation reaction of pyrophoric silane (SiH 4 ) with either oxygen or nitrous oxide created silica nanoparticles with diameters ranging from ∼22 to 90 nm in the presence of an inert background gas with a volume fraction of ca. 10 −4 , conditions necessary for gelation. The background gas was necessary for quick thermal quenching of freshly formed silica molecules and molten nanoparticles and some control of the particle size could be achieved by variation of the gas. The silica aerosol gels were found to have very low densities in the range 4-15 mg/cm 3 and high specific surface areas of 300-500 m 2 /g. Wide angle X-ray diffraction showed that the nanoparticles were amorphous silica. Neutron scattering showed that they were arranged in networks with a fractal dimension of 1.75 between 10 and 1000 nm length scales. INTRODUCTIONIn previous work, we presented an aerosol gelation method to produce porous materials with high specific surface area and extremely low density (Dhaubhadel et al. 2007). The method involved the gelation of nanoparticles in the aerosol phase to yield a material that we have named an "aerosol gel." Unlike wellknown aerogel materials which begin with a liquid phase sol-gel step, aerosol gels are made in the gas phase. Simply said a cloud of smoke in a volume gels or freezes to form a volume spanning, very light weight, porous body; truly "frozen smoke." The initial aerosol is composed of nanometer-sized particles produced rapidly by exploding in a chamber a hydrocarbon precursor with an oxidizer, e.g., oxygen. The nanometer particles so produced aggregate and then gel on the order of tens of seconds to form the aerosol gel. The carbon materials we made previously have densities as low as 2.5 mg/cc. The current state-of-the-art Address correspondence to C. M. Sorensen, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA. E-mail: sor@phys.ksu.edu for manufacture of aerogel materials is the sol-gel/supercriticaldrying method (Brinker and Scherer 1990; Hüsing and Schubert 1998). The gas phase aerosol gelation method is a significantly different than this state-of-the-art and hence might offer advantages because (1) there is no need for a supercritical drying step as for aerogels and (2) the aerosol gel method should be applicable to a greater variety of substances. Disadvantages of our method lie in the current need for a detonation which could be hard to scale up, and it is a batch process.Gelation is a consequence of random aggregation of noncoalescing particles to form ramified fractal aggregates. Fractal aggregates have a mass-size scaling exponent, the fractal dimension D f , that is less than the spatial dimension, d, and this inequality represents a fundamental condition for gelation (Sorensen and Chakrabarti 2011). Because of this, the ratio of aggregate mean nearest neighbor separation to aggregate size declines as the aggreg...

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Section: Morphology Of the Silica Aggregatessupporting

confidence: 58%

Synthesis of Silica Aerosol Gels via Controlled Detonation

Dhaubhadel

Rieker

Chakrabarti

et al. 2012

Aerosol Science and Technology

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“…Up till now, the most popular techniques used to determine the size of NPs include electron microscopy -TEM and SEM [193,194], and DLS for particles in suspension [195], and small-angle X-ray scattering (SAXS) [196]. TEM is the most direct method since size measurements can be obtained from particle images.…”

Section: Sizementioning

confidence: 99%

Heteroaggregation of nanoparticles with biocolloids and geocolloids

Wang

Adeleye

Huang

et al. 2015

Advances in Colloid and Interface Science

171

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The application of nanoparticles has raised concern over the safety of these materials to human health and the ecosystem. After release into an aquatic environment, nanoparticles are likely to experience heteroaggregation with biocolloids, geocolloids, natural organic matter (NOM) and other types of nanoparticles. Heteroaggregation is of vital importance for determining the fate and transport of nanoparticles in aqueous phase and sediments. In this article, we review the typical cases of heteroaggregation between nanoparticles and biocolloids and/or geocolloids, mechanisms, modeling, and important indicators used to determine heteroaggregation in aqueous phase. The major mechanisms of heteroaggregation include electric force, bridging, hydrogen bonding, and chemical bonding. The modeling of heteroaggregation typically considers DLVO, X-DLVO, and fractal dimension. The major indicators for studying heteroaggregation of nanoparticles include surface charge measurements, size measurements, observation of morphology of particles and aggregates, and heteroaggregation rate determination. In the end, we summarize the research challenges and perspective for the heteroaggregation of nanoparticles, such as the determination of α hetero values and heteroaggregation rates; more accurate analytical methods instead of DLS for heteroaggregation measurements; sensitive analytical techniques to measure low concentrations of nanoparticles in heteroaggregation systems; appropriate characterization of NOM at the molecular level to understand the structures and fractionation of NOM; effects of different types, concentrations, and fractions of NOM on the heteroaggregation of nanoparticles; the quantitative adsorption and desorption of NOM onto the surface of nanoparticles and heteroaggregates; and a better understanding of the fundamental mechanisms and modeling of heteroaggregation in natural water which is a complex system containing NOM, nanoparticles, biocolloids and geocolloids.

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“…In addition to the size distribution, magnetic properties were influenced by the composition of these nanoparticles. Another non-destructive technique to determine the size distribution is small angle X-ray scattering (SAXS) [12]. Its advantages are the accurate determination of nanoparticle size distributions and the discrimination between polydisperse single particle and polydisperse particle in aggregates.…”

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confidence: 99%

FePt3 nanosuspension synthesized from different precursors – a morphological comparison by SAXS, DLS and TEM

Sarmphim¹,

Soontaranon²,

Sirisathitkul³

et al. 2017

Bulletin of the Polish Academy of Sciences Technical Sciences

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Abstract. Annealed iron-platinum (FePt) is ferromagnetic in a nanoscale regime which is necessary for energy and data storage, whereas the as-synthesized form of FePt-based nanoparticles exhibits superparamagnetism useful for biomedical applications. In this study, as-synthesized nanosuspensions from the reaction of Pt(acac) 2 with Fe(acac) 3 and Fe(hfac) 3 are compared. X-ray diffraction (XRD) peaks for both samples are assigned to the FePt 3 phase. As shown by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS), nanoparticles synthesized by using Fe(acac) 3 have a smaller average diameter, but larger polydispersity index and particle agglomerations. On the other hand, the nanoparticles synthesized by using Fe(hfac) 3 can self-assemble into a longer range of patterned monolayer. Dynamic light scattering (DLS), measuring the size of cluster of nanoparticles as well as oleic acid and oleylamine at their surface, confirms that larger agglomerations in the sample were synthesized by using Fe(acac) 3 . In addition to the size distribution, magnetic properties were influenced by the composition of these nanoparticles. Another non-destructive technique to determine the size distribution is small angle X-ray scattering (SAXS) [12]. Its advantages are the accurate determination of nanoparticle size distributions and the discrimination between polydisperse single particle and polydisperse particle in aggregates. SAXS has been successfully used to complement TEM in probing the size distribution of several nanoparticles including Au [13], CoPt 3 [14] and FePt [15]. Furthermore, Fe 3 O 4 and CuO nanoparticles were comparatively characterized using X-ray diffractometry (XRD), TEM, DLS and SAXS [16].In this study, the morphology of FePt-based nanoparticles synthesized from two alternative precursors is compared by using TEM, DLS and SAXS. Iron(III) acetylacetonate (Fe(acac) 3 ) and iron(III) hexafluoroacetylacetone (Fe(hfac) 3 ) have been investigated as a replacement for highly toxic Fe(CO) 5 . The synthetic procedure, adapted from the published method [17], replaces a N 2 glove box with an Ar Schlenk line. The heating rate in the terminal process and revolution of purified centrifugation are also reduced.

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Particle Size Distribution Inferred from Small-Angle X-ray Scattering and Transmission Electron Microscopy

Cited by 80 publications

References 5 publications

Synthesis of Silica Aerosol Gels via Controlled Detonation

Synthesis of Silica Aerosol Gels via Controlled Detonation

Heteroaggregation of nanoparticles with biocolloids and geocolloids

FePt3 nanosuspension synthesized from different precursors – a morphological comparison by SAXS, DLS and TEM

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