The use of phase-inverting emulsions to show the phenomenon of interfacial crystallization on both heating and cooling

Journal of the American Chemical Society

Volumn 127, Issue 34, 2005, Pages 11894-11895

  Nicholson, Catherine E ^a   Cooper, Sharon J ^a   Marcellin, Claire ^a   Jamieson, Matthew J ^a  

^a DURHAM UNIVERSITY   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

DECANE; GLYCINE; POLYSORBATE 20; SORBITAN LAURATE; SURFACTANT; WATER; WATER OIL CREAM;

ARTICLE; COOLING; CRYSTALLIZATION; EMULSION; HEATING; MICROSCOPY; SCANNING ELECTRON MICROSCOPY; TEMPERATURE; X RAY DIFFRACTION;

EID: 24144490443     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja0526012     Document Type: Article

References (13)

1. Allen, K.; Davey, R. J.; Ferrari, E.; Towler, C.; Jones, M. O.; Pritchard, R. G. Cryst. Growth Des. 2002, 2, 523-527.
2. The numerous, small (tens of nanometers), transient self-assembled structures present at the PIT could adhere onto the growing nucleus and impede crystal growth. Individual surfactant molecules could also adsorb and cause some growth inhibition. However, we do not expect these to be dominant processes in this system, because the high glycine concentration of 27.4 wt % aids rapid crystal growth, droplet adhesion is not observed on any of the crystals, and the final morphologies reflect the normal aqueous morphologies of β-glycine, albeit that the PIT crystal morphology has mixed o/w and w/o crystal formation character. Furthermore, if growth inhibition was prevalent at the PIT, then the relative nucleation rate would increase, and we would expect a greater density of crystals to be produced, which is also not observed.
3. sat are the actual and saturation solute concentrations, respectively.
4. For a summary of classical nucleation theory, see: Sigsbee, R. A.; Pound, G. M. Adv. Colloid Interface Sci. 1967, 1, 335-390.
5. -1. However, irrespective of the precise value used, a dramatic increase in nucleation rate is always predicted.
6. -1 has been given for glycine in aqueous ethanol solutions. See: Walton, A. G. Formation and Properties of Precipitates; Wiley and Sons: New York, 1967. The greater solubility of glycine in water compared to that in ethanol is expected to provide an interfacial tension value lower than this.
7. -1 at 22 °C has been given for Span 20 at the decane-water interface. See: Peltonen, L.; Hirvonen, J.; Yliruusi, J. J. Colloid Interface Sci. 2001, 240, 272-276.
8. -1, which may reflect the inability of classical heterogeneous nucleation theory to model interfacial crystallization in emulsions.
9. This effect leads to the occurrence of a smaller maxima in the induction time at ∼ 15 °C for our 27.4 wt % aqueous glycine solutions.
10. The miscibility of the nucleation-promoting cosurfactant with Span 20 is likely to be a key parameter in the success of this strategy. For examples of interfacial crystallization induced in microemulsions and emulsions by doping with surface-active additives, see: (a) Jamieson, M. J.; Nicholson, C. E.; Cooper, S. J. Cryst. Growth Des. 2005, 5, 451-459.
11. (b) Davey, R. J.; Hilton, A. M.; Garside, J.; de la Fuente, M.; Edmondson, M.; Rainford, P. J. Chem. Soc., Faraday Trans. 1996, 92, 1927-1933.
12. (c) Kaneko, N.; Horie, T.; Ueno, S.; Yano, J.; Katsuragi, T.; Sato, K. J. Cryst. Growth 1999, 197, 263-270.
13. Sloutskin, E.; Bain, C. D.; Ocko, B. M.; Deutsch, M. Faradav Dicuss. 2005, 129, 339-352.