Chemical reactivity and the structure of gels

Brinker, C.J.; Bunker, Bruce C.; Tallant, D. R.; Ward, Katrina

doi:10.1051/jcp/1986830851

Cited by 43 publications

(21 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6. These ring structures have been identified by other workers who have classified the three membered rings as being the more reactive or "highenergy" sites on the surface (10,16,17). Upon rehydroxylation, there is a decrease in the peak at ∼600 cm −1 , which suggests a large reduction in the number of three-membered rings.…”

Section: Characterizationsupporting

confidence: 56%

Role of Surface Molecular Architecture and Energetics of Hydrogen Bonding Sites in Adsorption of Polymers and Surfactants

Bjelopavlic

Singh

El‐Shall

et al. 2000

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

Section: Characterizationsupporting

confidence: 56%

Role of Surface Molecular Architecture and Energetics of Hydrogen Bonding Sites in Adsorption of Polymers and Surfactants

Bjelopavlic

Singh

El‐Shall

et al. 2000

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

“…The silica network can be composed of very reactive chains or more stable condensed rings formed by SiO 4 tetrahedra. Chain conformation is often found in silicon‐based gels treated at low temperatures, whereas 3‐ or 4‐member rings are commonly found after heating between 300°C and 700°C 53, 54. When the gels are heated at temperatures close to the glassy transition, the structure evolves to 5‐ or 6‐member rings 54.…”

Section: Discussionmentioning

confidence: 99%

“…Chain conformation is often found in silicon‐based gels treated at low temperatures, whereas 3‐ or 4‐member rings are commonly found after heating between 300°C and 700°C 53, 54. When the gels are heated at temperatures close to the glassy transition, the structure evolves to 5‐ or 6‐member rings 54. In a previous study,55 we showed the influence of the CaO content on the evolution of the structural characteristics when 58S and 68S sol–gel glasses are stabilized at different temperatures.…”

Section: Discussionmentioning

confidence: 99%

A new quantitative method to evaluate the in vitro bioactivity of melt and sol‐gel‐derived silicate glasses

Arcos¹,

Greenspan²,

Vallet‐Regí³

2003

J Biomedical Materials Res

117

View full text Add to dashboard Cite

Two melt-derived glasses (45S5 and 60S) and four sol-gel glasses (58S, 68S, 77S, and 91S) have been synthesized. The activation energy for the silicon release was determined, and a very close correlation was observed between this value and published results of the bioactive behavior of the glasses. This relationship can be explained in terms of the influence of chemical composition, textural properties, and structural density on the silanol group formation and silicon dissolution. These measurements provide a quantitative method to evaluate the in vitro bioactivity of SiO(2)-based glasses. Preliminary studies suggest an activation energy gap (Ea) of 0.35-0.5 eV as a boundary between bioactive and nonbioactive glasses.

show abstract

“…The pore on the left has a surface consisting of metal-oxygen bonds and is characterized by surface energy VLV, while the surface of the pore on the right is covered with OR groups. Since those groups have low solubility in the solid phase, they must be expelled as the pore shrinks, and this requires an investment of energy, since the condensation reaction is endothermic in silica xerogels [9,10] (although it is exothermic in solution [ 11 ]). It is therefore necessary to add another term to the energy balance for sintering:…”

Section: Principles Of Sinteringmentioning

confidence: 99%

Sintering of sol-gel films

Scherer

1997

J Sol-Gel Sci Technol

View full text Add to dashboard Cite

Abstract. The sintering of films differs from that of bulk gels in several ways. The initial state of a film is generally denser and less crosslinked than a bulk gel made from the same sol, and these factors enhance the densification rate of the film. The substrate constrains the shrinkage of the film, leading to high stresses that retard densification and can influence phase changes. The substrate is a site for heterogeneous nucleation, and crystallization makes densification more difficult, so the competition between sintering and crystallization is particularly important for films. Fast heating favors densification over crystallization, so rapid thermal annealing usually produces denser films. The high surface to volume ratio of a thin film makes it susceptible to degradation by reaction with the substrate and the atmosphere, so choosing compatible materials and avoiding over-firing is essential.

show abstract

Chemical reactivity and the structure of gels

Cited by 43 publications

References 0 publications

Role of Surface Molecular Architecture and Energetics of Hydrogen Bonding Sites in Adsorption of Polymers and Surfactants

Role of Surface Molecular Architecture and Energetics of Hydrogen Bonding Sites in Adsorption of Polymers and Surfactants

A new quantitative method to evaluate the in vitro bioactivity of melt and sol‐gel‐derived silicate glasses

Sintering of sol-gel films

Contact Info

Product

Resources

About