Studies on Silicic Acid Gels. VI. Influence of Temperature and Acid upon the Time of Set.

Hurd, Charles B.

doi:10.1021/j150370a003

Cited by 10 publications

(8 citation statements)

References 5 publications

(5 reference statements)

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“…By considering the process as a chemical reaction, they obtained a value for the energy of activation for the process of 16,640 calories. As a result of further studies, Hurd (32) has shown that the energy of activation is practically the same using either acetic, citric, succinic, or tartaric acid, all, of course, being weak acids.…”

Section: The Sol-gel Transformation or Setting Of The Gelmentioning

confidence: 95%

Theories for the Mechanism of the Setting of Silicic Acid Gels.

Hurd¹

1938

Chem. Rev.

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Section: The Sol-gel Transformation or Setting Of The Gelmentioning

confidence: 95%

Theories for the Mechanism of the Setting of Silicic Acid Gels.

Hurd¹

1938

Chem. Rev.

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“…The thickness and porosity of the cell walls depends on the concentration (density) of silicate species used in the gel 72. The gelation time varies with silicate reactant concentration,101 pH,102 temperature,103 and the identity of the acid catalyst104 and affects the final structure of the hydrogel network. For example, acidification with stronger acid results in longer gelation times, forming acidic gels that are composed of networks with particulate character (Figure 1h).…”

Section: Introductionmentioning

confidence: 99%

Crystal Growth of Calcium Carbonate in Hydrogels as a Model of Biomineralization

Asenath‐Smith

Keene

et al. 2012

Adv Funct Materials

198

307

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A gel is defi ned as a two-component (solid and liquid), continuous, solid-like material with viscoelastic rheological Crystal Growth of Calcium Carbonate in Hydrogels as a Model of BiomineralizationIn recent years, the prevalence of hydrogel-like organic matrices in biomineralization has gained attention as a route to synthesizing a diverse range of crystalline structures. Here, examples of hydrogels in biological, as well as synthetic, bio-inspired systems are discussed. Particular attention is given to understanding the physical versus chemical effects of a broad range of hydrogel matrices and their role in directing polymorph selectivity and morphological control in the calcium carbonate system. Finally, recent data regarding hydrogel-matrix incorporation into the growing crystals is discussed and a mechanism for the formation of these single-crystal composite materials is presented. Future and is researching crystal growth in gels as a means to form nanocomposites.chains form helices (double or single helices) that subsequently aggregate into three-dimensional (3D) bundles, forming a porous network with fi brous characteristics (Figure 1 a,b). [ 82 , 83 ] Both the gelling and melting temperatures can be tailored by chemical modifi cation such as partial hydroxyethylation. [ 84 ] The mechanical behavior of agarose gels is sensitive to molecular weight and concentration [ 85 ] as well as chemical modifi cation.

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“…1 (charge has been ignored for clarity). The sensitivity of the chemistry toward temperature, ionic strength, and particularly pH [1][2][3][4][5][6][7] only complicates experimental attempts at mechanistic elucidation further.…”

Section: Introductionmentioning

confidence: 99%

Theoretical investigations into the nucleation of silica growth in basic solution part I – ab Initio studies of the formation of trimers and tetramers

McIntosh

2013

Phys. Chem. Chem. Phys.

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We have performed the first ab initio study that considers all possible oligomerization reactions available to silicic acid in basic solution (ignoring high-energy multiply charged species), up to and including tetramers. Energies have been computed at the MP2/6-31+G(d)//HF/6-31+G(d) level of theory, with a hybrid solvation model which includes explicit waters and CPCM continuum corrections to account for solvent effects. The explicit waters have been found to be extremely important in providing additional stabilization of intermediates and transition states which are not accounted for properly by more conventional implicit solvent approaches, suggesting some of the known pathways are more facile than previously predicted. Additionally, a number of previously neglected bimolecular growth pathways such as dimer/dimer and monomer/cyclic trimer additions, and unimolecular cyclization steps such as branched 3-ring formation from branching tetramers and the formation of highly condensed bicyclic and tetrahedral clusters have been studied in detail. Many are found to be very energetically feasible and consequently could have considerable impacts on the initial stages of silica nucleation.

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Studies on Silicic Acid Gels. VI. Influence of Temperature and Acid upon the Time of Set.

Cited by 10 publications

References 5 publications

Theories for the Mechanism of the Setting of Silicic Acid Gels.

Theories for the Mechanism of the Setting of Silicic Acid Gels.

Crystal Growth of Calcium Carbonate in Hydrogels as a Model of Biomineralization

Theoretical investigations into the nucleation of silica growth in basic solution part I – ab Initio studies of the formation of trimers and tetramers

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