Pore Structure Analysis Via Small Angle X-Ray Scattering And Contrast Matching

Hua, Duen-Wu; D'souza, Julius; Schmidt, P. W.; Smith, Douglas M.

doi:10.1016/s0167-2991(08)63085-2

Cited by 23 publications

(8 citation statements)

References 6 publications

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“…Such slopes are well above what would be expected from Porod law behavior (slope of −4) and are attributed to the effect of a gradation in electron density associated with the trimethyl groups attached to the silica framework. This effect has been observed in related systems and has been discussed in terms of a “fuzzy boundary” by Hua et al In the lower q region, slope changed for short aging time (0.5 h) from about −1.8 to −2, but thereafter decreased to −1.7 after 3 h. As aging proceeded, a crossover region became more pronounced, and shifted to lower q (from about 0.8 to about 1.2 nm).…”

Section: Resultssupporting

confidence: 56%

A Convenient Synthesis of Silylated Silica Xerogels

et al. 1999

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Treated silica xerogels with controlled porosity and surface area were prepared by the in situ treatment of hydrogels with hexamethyldisiloxane or alkylchlorosilanes in the presence of isopropyl alcohol. The resulting hydrogels were hydrophobic and readily transferred to nonpolar organic solvents upon contact. The surface area and porosity of the xerogel were controlled by varying the pH, time, and temperature used to polymerize the hydrogel prior to treatment. In general, the surface area decreased with increases in aging time or temperature, whereas the total pore volume and pore size increased. Silylation of the hydrogel in the aqueous phase retains the structure of the hydrogel and permits isolation with minimum structure collapse. By using this technique, silylated xerogels with surface areas ranging from 200 to >700 m2/g and pore volumes of 1.5 to 3.8 cm3/g were obtained.

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Section: Resultssupporting

confidence: 56%

A Convenient Synthesis of Silylated Silica Xerogels

et al. 1999

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“…Right system with matching fl uid present at it appears to the scattering experiment. , 1978Beaudry et al 1976;Williams et al 1979;Akcasu et al 1980;Jahshan and Summerfi eld 1980;Koberstein 1982;Hadziioannou et al 1982;Bates et al 1983;Hasegawa et al 1985Hasegawa et al , 1987Allen 1991;Hua et al 1994;Smarsley et al 2001;Littrell et al 2002;Connolly et al 2006;Stuhrmann and Heinrich 2007;Ruppert et al 2013;Thomas et al 2014). This is because the scattering length density for neutrons depends on the isotope, rather than just the element involved, and there is a very large difference in scattering length density between hydrogen and deuterium, and thus between H 2 O (neutron sld = -0.56 × 10 10 cm -2 ) and D 2 O (neutron sld = 6.392 × 10 10 cm -2 ).…”

Section: Contrast Matchingmentioning

confidence: 99%

Characterization and Analysis of Porosity and Pore Structures

Anovitz

Cole

2015

Reviews in Mineralogy and Geochemistry

830

480

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“…However, because of this Babinette principle, sometimes it is very difficult to decide if the observed scattering has to be attributed to scattering by pores or by particles. In this case, contrast variation might be helpful: if pores are filled with a liquid of equal density, the scattering will (Hua et al 1994;Vrieling et al 2000).…”

Section: Small-angle X-ray Scatteringmentioning

confidence: 99%

Silicon Biomineralisation: Towards Mimicking Biogenic Silica Formation in Diatoms

Vrieling¹,

Hazelaar²,

Gieskes

et al. 2003

Silicon Biomineralization

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IntroductionSilica is by far the most abundant compound in the earth's crust. It serves various functions in nature: organisms ranging from lower eukaryotes to plants use it as one of the biominerals that provide support, protection, strength, or tools in various functions. Biogenic silica is the least studied of the biominerals. The best-studied ones (Hunter 1996) are composed of calcium (apatite, enamel, calcite); these are present in the bone tissue and teeth of mammals and in the shells of shellfish. In contrast to calcium minerals, relatively little is known about the formation of biogenic silica. The most likely function of biogenic silica in unicellular organisms seems to be giving strength to the living cell; good examples from the aquatic environment are siliceous (exo)skeletons or cell casings of the microalgal groups of diatoms ( Fig. 1) and silicoflagellates, and of Radiolaria (Simpson and Volcani 1981; Pickett-Heaps et al. 1990;Round et al. 1990).Silica and silica-based materials (e.g. zeolites and MCM-type materials) are also widely used in a variety of industrial and technological applications. A limited number of micro-and mesoporous silicas serve as fillers in rubber materials (e.g. in tyres), as catalyst supports, as drying agents, as abrasives (e.g. toothpastes), or as filters in separation technologies (Iler 1979;Brinker and Scherer 1990;Bergna 1994). A prerequisite for each application is that a silica with specific properties of mechanical strength, pore volume, pore-size distribution, or specific surface area is required. The current demand for "the best" silicas in these respects is increasing and a search for new, improved or alternative artificial silica materials has been going on for a few years. Biogenic silica sources also have received more attention lately (Morse 1999;Vrieling et al. 1999b). It is expected that if nature can be mimicked, a wide range of innovative and new tailor-made silicas can be produced approaching the variety in architecture seen in nature, e.g. in the algal class of diatoms (Vrieling et al.

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Pore Structure Analysis Via Small Angle X-Ray Scattering And Contrast Matching

Cited by 23 publications

References 6 publications

A Convenient Synthesis of Silylated Silica Xerogels

A Convenient Synthesis of Silylated Silica Xerogels

Characterization and Analysis of Porosity and Pore Structures

Silicon Biomineralisation: Towards Mimicking Biogenic Silica Formation in Diatoms

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