Hostname: page-component-76fb5796d-x4r87 Total loading time: 0 Render date: 2024-04-25T15:48:17.230Z Has data issue: false hasContentIssue false
  • English
  • Français

Water Mobility in Reverse Micelles Studied by Quasielastic Neutron Scattering and Molecular Dynamics Simulation

Published online by Cambridge University Press:  26 February 2011

Branka Ladanyi  and
Nancy Levinger
Branka Ladanyi
Affiliation:
bl@lamar.colostate.edu, Colorado State University, Chemistry, Department of Chemistry, Fort Collins, Colorado, 80523-1872, United States, 970-491-5196, 970-491-3361
Nancy Levinger
Affiliation:
Levinger@lamar.colostate.edu, Colorado State University, Chemistry, United States
Get access

Abstract

Reverse micelles (RMs) are aggregates in which nanoscale droplets of a polar liquid, usually water, are surrounded by a surfactant layer in a nonpolar continuous phase. They are widely used as media for reactions in which the extent of confinement or the presence of a surfactant interface play a central role. We have used molecular dynamics (MD) computer simulation and quasielastic neutron scattering (QENS) and to investigate the mobility of water molecules in reverse micelles. The contribution of water to the QENS signal is enhanced by deuterating the surfactant and the nonpolar phase. Our studies of water mobility have focused on the effects of water pool size, determined by the water/surfactant mole ratios w0, as well as on the properties of the water-surfactant interface. Specifically, we have examined the effects of varying w0 and of substituting other alkali ions for the usual Na+ counterion of the anionic surfactant AOT (bis (2-ethylhexyl) sulfosuccinate)). We find good agreement between the QENS signal and its prediction from MD simulation. This allows us to obtain additional insight into water mobility by analyzing the MD self-intermediate scattering function (ISF) of water hydrogens in terms of contributions from molecular rotation and translation and from molecules in different interfacial layers. MD data indicate that the translational ISF decays nonexponentially due to lower water mobility close to the interface and to confinement-induced restrictions on the range of translational displacements. Rotational relaxation also exhibits nonexponential decay. However, rotational mobility of O-H bond vectors in the interfacial region remains fairly high due to the lower density of water-water hydrogen bonds in the vicinity of the interface.

Keywords

neutron scatteringsimulationnanostructure
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 899: Symposium N – Dynamics in Small Confining Systems VIII , 2005 , 0899-N05-01
Copyright
Copyright © Materials Research Society 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Pileni, M. P., Journal of Physical Chemistry 97, 6961 (1993).Google Scholar
2. Luisi, P. L. and Straub, B. E., Reverse Micelles: Biological and Technological Relevance of Amphiphilic Structures in Apolar Media. (Plenum, New York, 1984).Google Scholar
3. Amararene, A., Gindre, M., LeHuerou, J. Y., Nicot, C., Urbach, W., and Waks, M., J. Phys. Chem. B 101, 10751 (1997).Google Scholar
4. Amico, P., D'Angelo, M., Onori, G., and Santucci, A., Nuovo Cimento 17, 1053 (1995).Google Scholar
5. Boicelli, C. A., Giomini, M., and Giuliani, A. M., Appl. Spec. 38, 537 (1984).Google Scholar
6. Brubach, J. B., Mermet, A., Filabozzi, A., Gerschel, A., Lairez, D., Krafft, M. P., and Roy, P., J. Phys. Chem. B 105, 430 (2001).Google Scholar
7. D'Angelo, M., Fioretto, D., Onori, G., Palmieri, L., and Santucci, A., Phys. Rev. E 54, 993 (1996).Google Scholar
8. Venables, D. S., Huang, K., and Schmuttenmaer, C. A., J. Phys. Chem. B 105, 9132 (2001).Google Scholar
9. Bée, M., Quasielastic Neutron Scattering. (Hilger, Bristol, 1988).Google Scholar
10. Harpham, M. R., Ladanyi, B. M., Levinger, N. E., and Herwig, K. W., J. Chem. Phys. 121, 7855 (2004).Google Scholar
11. Herwig, K. W., Dozier, W. D., and Huang, J. S., Mater. Res. Using Cold Neutrons Pulsed Neutron Sources, [Proc.], 95 (1999).Google Scholar
12. Bellissent-Funel, M. C., Chen, S. H., and Zanotti, J. M., Phys. Rev. E 51, 4558 (1995).Google Scholar
13. Bellissent-Funel, M. C., J. Mol. Liq. 78, 19 (1998).Google Scholar
14. Zanotti, J. M., Bellissent-Funel, M. C., and Chen, S. H., Phys. Rev. E: 59, 3084 (1999).Google Scholar
15. Crupi, V., Majolino, D., Migliardo, P., and Venuti, V., J. Phys. Chem. B 106, 10884 (2002).Google Scholar
16. Crupi, V., Majolino, D., Migliardo, P., and Venuti, V., Philos. Mag. B 82, 425 (2002).Google Scholar
17. Mitra, S., Mukhopadhyay, R., Pillai, K. T., and Vaidya, V. N., J. Non-Cryst. Solids 235, 229 (1998).Google Scholar
18. Mitra, S., Mukhopadhyay, R., Pillai, K. T., and Vaidya, V. N., Solid State Commun. 105, 719 (1998).Google Scholar
19. Mitra, S., Mukhopadhyay, R., Tsukushi, I., and Ikeda, S., J. Phys.-Condens. Matter 13, 8455 (2001).Google Scholar
20. Takamuku, T., Yamagami, M., Wakita, H., Masuda, Y., and Yamaguchi, T., J. Phys. Chem. B 101, 5730 (1997).Google Scholar
21. Takahara, S., Nakano, M., Kittaka, S., Kuroda, Y., Mori, T., Hamano, H., and Yamaguchi, T., J. Phys. Chem. B 103, 5814 (1999).Google Scholar
22. Chen, S. H., Gallo, P., and Bellissent-Funel, M. C., Can. J. Phys. 73, 703 (1995).Google Scholar
23. Faraone, A., Liu, L., Mou, C. Y., Shih, P. C., Copley, J. R. D., and Chen, S. H., J. Chem. Phys. 119, 3963 (2003).Google Scholar
24. Venturini, F., Gallo, P., Ricci, M. A., Bizzarri, A. R., and Cannistraro, S., Philos. Mag. B 82, 507 (2002).Google Scholar
25. Venuti, V., Crupi, V., Magazu, S., Majolino, D., Migliardo, P., and Bellissent-Funel, M. C., J. Phys. IV 10, 211 (2000).Google Scholar
26. Teixeira, J., Nuovo Cimento 16, 1433 (1994).Google Scholar
27. Gallo, P., Rovere, M., and Spohr, E., J. Chem. Phys. 113, 11324 (2000).Google Scholar
28. Gallo, P., Phys.l Chem. Chem. Phys. 2, 1607 (2000).Google Scholar
29. Gallo, P., Rapinesi, M., and Rovere, M., J. Chem. Phys. 117, 369 (2002).Google Scholar
30. Gallo, P., Ricci, M. A., and Rovere, M., J. Chem. Phys. 116, 342 (2002).Google Scholar
31. Rovere, M., Ricci, M. A., Vellati, D., and Bruni, F., J. Chem. Phys. 108, 9859 (1998).Google Scholar
32. Chen, S. H., Gallo, P., Sciortino, F., and Tartaglia, P., Phys. Rev. E 56, 4231 (1997).Google Scholar
33. Faraone, A., Liu, L., and Chen, S. H., J. Chem. Phys. 119, 6302 (2003).Google Scholar
34. Eicke, H. F. and Rehak, J., Helv. Chim. Acta 59, 2883 (1976).Google Scholar
35. Harpham, M. R., Ladanyi, B. M., and Levinger, N. E., J. Phys. Chem. B 109, 16891 (2005).Google Scholar
36. Di Cola, D., Deriu, A., Sampoli, M., and Torcini, A., J. Chem. Phys. 104, 4223 (1996).Google Scholar
37. Egelstaff, P. A., An Introduction to the Liquid State. (Academic, London, 1967).Google Scholar
38. Volino, F. and Dianoux, A. J., Mol. Phys. 41, 271 (1980).Google Scholar
39. Sears, V. F., Can. J. Phys. 45, 237 (1967).Google Scholar
40. Faeder, J. and Ladanyi, B. M., J. Phys. Chem. B 104, 1033 (2000).Google Scholar
41. Lee, C. Y., McCammon, J. A., and Rossky, P. J., J. Chem. Phys. 80, 4448 (1984).Google Scholar
42. Berendsen, H. J. C., Grigera, J. R., and Straatsma, T. P., J. Phys. Chem. 91, 6269 (1987).Google Scholar
43. Schweighofer, K. J., Essmann, U., and Berkowitz, M., J. Phys. Chem. B 101, 10775 (1997).Google Scholar
44. Dang, L. X., J. Am. Chem. Soc. 117, 6954 (1995).Google Scholar
45. Teixeira, J., Bellissent-Funel, M. C., Chen, S. H., and Dianoux, A. J., Phys. Rev. A 31, 1913 (1985).Google Scholar
46. Tan, H. S., Piletic, I. R., and Fayer, M. D., J. Chem. Phys. 122 (2005).Google Scholar
47. Lynden-Bell, R. M. and Steele, W. A., J. Phys. Chem. 88, 6514 (1984).Google Scholar
48. Tarek, M. and Tobias, D. J., Biophys. J. 79, 3244 (2000).Google Scholar
49. Faeder, J., Albert, M. V., and Ladanyi, B. M., Langmuir 19, 2514 (2003).Google Scholar
50. Senapati, S. and Berkowitz, M. L., J. Phys. Chem. A 108, 9768 (2004).Google Scholar
51. Eastoe, J., Towey, T. F., Robinson, B. H., Williams, J., and Heenan, R. K., J. Phys. Chem. 97, 1459 (1993).Google Scholar
52. Fioretto, D., Freda, M., Mannaioli, S., Onori, G., and Santucci, A., J. Phys. Chem. B 103, 2631 (1999).Google Scholar
53. Fioretto, D., Freda, M., Onori, G., and Santucci, A., J. Phys. Chem. B 103, 8216 (1999).Google Scholar
54. Riter, R. E., Undiks, E. P., and Levinger, N. E., J. Am. Chem. Soc. 120, 6062 (1998).Google Scholar
55. Pant, D., Riter, R. E., and Levinger, N. E., J. Chem. Phys. 109, 9995 (1998).Google Scholar