Abstract
We have used small angle neutron scattering (SANS) to study solutions of cetyltrimethylammonium 2,6-dichlorobenzoate (2,6) at rest and as a function of shear. These solutions are Newtonian, and up to a concentration of at least 100mM contain spherical micelles. Comparison with viscoelastic solutions of the closely related, and much studied, cetyltrimethylammonium 3,5-dichlorobenzoate (3,5) is made. While spheres are not expected to align under shear, a shear induced sphere to rod transition has been postulated for this system. In the results presented here, no shear induced sphere to rod transition was observed even at the highest accessible shear rate. Addition of sufficient supporting electrolyte (up to 1M NaCl) does cause such a transition in the quiescent solution. Hoffmann et al. have seen what they refer to as the formation of a shear induced structure (SIS or type II micelles) on similar systems where short rods form in the absence of supporting electrolyte. Shearing of the salted system produces rapid though not spectacular alignment, with no evidence of a SIS forming.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
P. Debye, and E. Anacker, J. Phys. Colloid Chem. 55, 644 (1951).
S. Gravsholt , J. Colloid Interface Sci. 57, 575 (1976).
T. Imae, J. Phys. Chem 94, 5953 (1990).
H. Rehage, and H. Hoffmann, Faraday Discuss. Chem. Soc. 76, 363 (1983).
W. A. Hamilton, P. D. Butler, S. M. Baker, G. S. Smith, J. B. Hayter, L. J. Magid, and R. Pynn., Phys. Rev. Lett. 72, 2219 (1994).
P. D. Butler, L. J. Magid, W. A. Hamilton, J. B. Hayter, B. Hammouda, and P. J. Kreke, submitted to Phys. Rev. Lett.
P. D. Butler, L. J. Magid, and J. B. Hayter, Flexibility of Cetyltrimethylammonium 3,5-dichlorobenzoate Micelles in Structure and Flow in Surfactant Solutions; C. A. Herb and R. K. Prud’homme, Eds.; ACS Symposium Series 283; American Chemical Society: Washington, D.C., chapter 17 (1994).
Unpublished results.
L. J. Magid, J. C. Gee, and Y. Talmon, Langmuir 6, 1609 (1990).
J. Kalus, H. Hoffmann, and K. Ibel, Colloid Polym. Sci. 267, 818 (1989).
J. Kalus, H. Hoffmann, S. -H. Chen, and P. Lindner, J. Phys. Chem. 93, 4267 (1989).
M. T. Carver, Ph.D. dissertation, University of Tennessee, Knoxville, TN, 1986.
P. J. Kreke, Ph.D. dissertation, University of Tennessee, Knoxville, TN, 1993.
J. B. Hayter and J. Penfold, J. Phys. Chem. 88, 4589 (1984).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Butler, P.D., Magid, L.J., Hamilton, W.A. et al. Effects of Shear on the Structures in a System of Small Rodlike Micelles. MRS Online Proceedings Library 376, 313–316 (1994). https://doi.org/10.1557/PROC-376-313
Published:
Issue Date:
DOI: https://doi.org/10.1557/PROC-376-313