Kinetics of Nucleation and Crystal Growth

The nucleation kinetics of hen egg-white lysozyme crystallization was investigated using a hot stage cooling crystallizer and a microscope to monitor the solution crystallization process in real time. Images of crystals were continuously recorded under varied precipitant and protein concentrations. The nucleation rate was found to be higher at higher precipitant concentration, and increase monotonically with protein concentration if the precipitant concentration was held 2 constant. Attempt was made to interpret the experimental data using classical nucleation theory. It was found that the model predictions are lower than the experimental values at low supersaturations but agree well with experimental data at high supersaturations. The trends in the experimental data suggest that two nucleation mechanisms might co-exist: heterogeneous nucleation seeming to be the dominant at low supersaturation while at higher supersaturation homogeneous nucleation seeming to play the major role.

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“…Primary nucleation can occur homogenously or heterogeneously [16]. Supersaturation controls the dominant mechanisms [17].…”

Section: Nucleation Ratementioning

confidence: 99%

Study on nucleation kinetics of lysozyme crystallization

Chen

Zhang

Liu

et al. 2017

Journal of Crystal Growth

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“…65 Additive ions occupying growth sites disrupt growth leading to the formation of protuberances (nuclei) on the surface. 66,67 These observations point to growth at a high supersaturation, in agreement with G.I. results.…”

Section: Phases and Morphologymentioning

confidence: 99%

Interaction between Epsomite Crystals and Organic Additives

Ruíz-Agudo

Putnis

Rodríguez-Navarro

2008

Crystal Growth & Design

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A number of phosphonates and carboxylates were tested as potential crystallization inhibitors for epsomite (MgSO 4 · 7H 2 O). Epsomite nucleation is strongly inhibited in the presence of amino tri(methylene phosphonic acid) (ATMP), diethylenetriaminepentakis (methylphosphonic acid) (DTPMP), and poly(acrylic acid) sodium salt (PA). These additives also act as habit modifiers promoting the growth of acicular crystals elongated along the [001] direction. Environmental scanning electron microscopy (ESEM), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and molecular modeling of additive adsorption on specific epsomite (hkl) faces are used to identify how these additives inhibit epsomite crystallization. Additives attach preferentially on epsomite {110} faces, at edges of monolayer steps parallel to [001].Step pinning and the eventual arrest of step propagation along 〈110〉 directions account for the observed habit change. Hydrogen bonding between the functional groups of additive molecules and water molecules in epsomite {110} appears to be the principal mechanism of additive-epsomite interaction, as shown by FTIR and molecular modeling. Molecular modeling also shows that DTPMP displays a high stereochemical matching with epsomite {110} surfaces, which can explain why this is the most effective inhibitor tested. The use of such effective crystallization inhibitors may lead to more efficient preventive conservation of ornamental stone affected by epsomite crystallization damage.

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“…11 The phase diagram for the binary SDS-H 2 O system is well-established, [12][13][14] shown in Figure 1. For a crystalline dispersion the polymorph, morphologies and size distributions of the crystals has profound processing and performance implications, [15][16][17] including: how the material flows and settles 18 its rate of dissolution, 19 optical appearance, texture and rheology. 10 Needle-shaped crystals, for instance, are often undesirable during processing due to their high aspect ratio.…”

Section: Introductionmentioning

confidence: 99%

Isothermal Crystallization Kinetics of Sodium Dodecyl Sulfate–Water Micellar Solutions

Miller¹,

Poulos²,

Robles

et al. 2016

Crystal Growth & Design

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KingdomThe crystallization mechanisms and kinetics of micellar sodium dodecyl sulfate (SDS) solutions in water, under isothermal conditions, were investigated experimentally by a combination of reflection optical microscopy (OM), differential scanning calorimetry (DSC) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The rates of nucleation and growth were estimated from OM and DSC across temperatures ranging from 20 to -6 °C for 20% SDS-H 2 O, as well as for 10 and 30% SDS-H 2 O at representative temperatures of 6, 2 and -2 °C. A decrease in temperature increased both nucleation and growth rates, and the combined effect of the two processes on the morphology was quantified via both OM and ATR-FTIR. Needles, corresponding to the hemihydrate polymorph, become the dominant crystal form at ≤-2 °C, while platelets, the monohydrate, predominate at higher temperatures. Above 8 °C, crystallization was only observed if seeded from crystals generated at lower temperatures. Our results provide quantitative and morphological insight into the crystallization of ubiquitous micellar SDS solutions and its phase stability below room temperature. ABSTRACT:The crystallization mechanisms and kinetics of micellar sodium dodecyl sulfate (SDS) solutions in water, under isothermal conditions, were investigated experimentally by a combination of reflection optical microscopy (OM), differential scanning calorimetry (DSC) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The rates of nucleation and growth were estimated from OM and DSC across temperatures ranging from 20 to -6 °C for 20% SDS-H 2 O, as well as for 10 and 30% SDS-H 2 O at representative temperatures of 6, 2 and -2 °C. A decrease in temperature increased both nucleation and growth rates, and the combined effect of the two processes on the morphology was quantified via both OM and ATR-FTIR. Needles, corresponding to the hemihydrate polymorph, become the dominant crystal form at ≤-2 °C, while platelets, the monohydrate, predominate at higher temperatures. Above 8 °C, crystallization was only observed if seeded from crystals generated at lower temperatures. Our results 3 provide quantitative and morphological insight into the crystallization of ubiquitous micellar SDS solutions and its phase stability below room temperature.

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Kinetics of Nucleation and Crystal Growth

Cited by 51 publications

References 31 publications

Study on nucleation kinetics of lysozyme crystallization

Study on nucleation kinetics of lysozyme crystallization

Interaction between Epsomite Crystals and Organic Additives

Isothermal Crystallization Kinetics of Sodium Dodecyl Sulfate–Water Micellar Solutions

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