Precipitation and association of silver laurate in aqueous solutions

Hrust, Vesna; Kallay, Nikola; Težak, Đurđica

doi:10.1007/bf01410393

Cited by 9 publications

(5 citation statements)

References 21 publications

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“…From the precipitation phase boundaries in Figures 1 and 2, the CMC for SDS is 0.0067 M (14) and for SOBS is 0.012 M. These values are consistent with the CMC values obtained from surface tension measurements: 0.0072 M for SDS and 0.012 M for SOBS (20). Several reviews have discussed the thermodynamics (e.g., phase diagrams or Krafft temperatures) of anionic surfactant precipitation with metal ions (4,21,22).…”

Section: Resultsmentioning

confidence: 99%

Kinetics of precipitation of surfactants. I. Anionic surfactants with calcium and with cationic surfactants

Rodriguez

Lowery

Scamehorn

et al. 2001

J Surfact & Detergents

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Isoperibol calorimetry was used to measure the rates of precipitation for aqueous solutions of several anionic surfactants with calcium and of anionic and cationic surfactants. A monomer concentration-dependent supersaturation ratio was used to describe the relative rates of precipitation for the surfactant systems studied. This supersaturation ratio allows for the relative rates of precipitation of any surfactant solution to be compared whether micelles are present in solution or not. In general, as the supersaturation ratio increases, the rate of precipitation decreases and the induction time decreases, both above and below the critical micelle concentration (CMC). The rate of precipitation of sodium dodecyl sulfate (SDS) with dodecyl pyridinium chloride is much slower than the rate of precipitation of the anionic surfactants with calcium for similar supersaturation ratios. The rate of precipitation of SDS with calcium is slightly faster than the rate of precipitation of sodium octyl benzene sulfonate for similar supersaturation ratios. Studies of precipitate crystals, conducted using image analysis, showed that size and shape depended on the initial supersaturation, the precipitating surfactant molecule, and the extent of aging (until an equilibrium size and shape was reached). Also, differences in the appearance of crystals formed from solutions above and below the CMC were observed. These were most likely due to the difference in supersaturation of these solutions. The crystals formed due to precipitation of SDS with calcium at a concentration above the CMC formed flat trapezoidal, rhombic, and hexagonal shapes. These aged into clusters by 1 wk. For a solution that was precipitated at concentrations beginning below the CMC, the crystals began as elongated and rhombic flat plates and aged into trapezoidal, rhombic, and needle-like structures.

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Section: Resultsmentioning

confidence: 99%

Kinetics of precipitation of surfactants. I. Anionic surfactants with calcium and with cationic surfactants

Rodriguez

Lowery

Scamehorn

et al. 2001

J Surfact & Detergents

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“…Sodium carboxylate salts, especially of long chain (C 12 and longer) carboxylic acids, have been investigated in great detail over many years [15][16][17]; however, the formation of the corresponding silver carboxylates is far less understood [1,[18][19][20][21]. The solid-state structure of the silver carboxylates plays an important role in the imaging properties of the materials [2], and the majority of publications on this silver carboxylate preparation are patents that claim various preparation methods [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Silver carboxylate nanostructure nucleation and growth on AgBr crystals

Dong¹,

Whitcomb²,

McCormick³

et al. 2005

Nanotechnology

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The initial stage of the reaction between sodium stearate (NaSt) and AgNO(3) produces silver stearate (AgSt) micelles, [(C(18)H(35)O(2))(x)(Na(x-y))(Ag(y))(H(2)O)(z)], and aggregations of these AgSt micelles in the form of cubic pre-AgSt crystals. When cubic grains of 50 nm AgBr are added to the NaSt dispersion prior to the AgNO(3), the reaction proceeds to form the silver stearate micelles, but not the aggregation of those micelles. Instead, the {111} silver ion planes of the cubic AgBr crystal corners provide nucleation sites for silver stearate micelle deposition and crystal growth. After nucleation, the AgSt micelles evolve into nanostructured bud-like formations via an epitaxial interface on one or several corners of each AgBr cubic crystal. Over time, additional AgSt micelle deposition enables the buds to grow longer into strand-like structures, which then connect to form the beginnings of the ultimate silver stearate crystal plates.

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“…While sodium soaps (long-chain carboxylates having chain lengths between 12 and 24) have been investigated in great detail over many years, − the details concerning the formation of the corresponding silver soaps are far less understood . Unbeknownst to the inventors of photothermography, the solid-state structure of the silver soaps plays an important role in the imaging properties of the materials. , Most publications on this topic are patents that typically do not discuss a fundamental understanding of the effect of the reaction conditions on the formation of the silver soap. − Normally, the simple addition of a soluble silver ion, such as silver nitrate, to the sodium soap is sufficient to rapidly exchange metal ions and precipitate the silver soap.…”

Section: Introductionmentioning

confidence: 99%

Crystallization of Silver Stearate from Sodium Stearate Dispersions

et al. 2004

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Silver carboxylates, the common silver source used for photothermographic imaging materials, are normally obtained from the reaction between sodium soap (e.g., sodium stearate) and silver nitrate. They form platelet-like crystals with a lamellar structure in water at room temperature. Light microscopy investigations reveal that the formation of silver stearate (AgSt) crystals follows a diffusion-controlled mechanism. The reaction between the sodium soap and silver nitrate preferentially occurs in solution rather than on the soap fiber solid interface. Cryogenic transmission electron microscopy, together with an on-the-grid reaction technique, provides a useful tool to directly image silver stearate microstructures at the initial stages of AgSt precipitation. The AgSt reaction product first forms particles about 5 nm in size, which is similar to the d-spacing of final AgSt crystals. Those particles aggregate to produce larger and loosely packed embryonic crystals, the precursors to the ultimate silver stearate crystals.

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Precipitation and association of silver laurate in aqueous solutions

Cited by 9 publications

References 21 publications

Kinetics of precipitation of surfactants. I. Anionic surfactants with calcium and with cationic surfactants

Kinetics of precipitation of surfactants. I. Anionic surfactants with calcium and with cationic surfactants

Silver carboxylate nanostructure nucleation and growth on AgBr crystals

Crystallization of Silver Stearate from Sodium Stearate Dispersions

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