Effect of shear on the structures in a system of small rodlike micelles

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:225273

Butler, P D; Magid, L J; Kreke, P J ^[1]; Hamilton, W A; Hayter, J B ^[2]

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1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry
2. Oak Ridge National Lab., TN (United States). Solid State Div.

The authors 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 100 mM 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 2 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.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 225273
• Report Number(s): CONF-941144--; ISBN 1-55899-278-2
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
DIAGNOSTIC TECHNIQUES
MICELLAR SYSTEMS
MICROSTRUCTURE
NEUTRONS
SHEAR
SMALL ANGLE SCATTERING