Abstract
The structure of a cationic worm-like cylindrical micelle was investigated by SANS (small-angle neutron scattering). Intensities from 0.1% by weight solutions in D2O, at rest and under shear, were measured on the NIST Cold Neutron Research facility 30-m spectrometer in the wave vector range 0.03⩽Q (nm1)⩽-2.0. Scattered intensity patterns from the solutions subjected to shears equal to or greater than 40s1 showed pronounced anisotropy, but such anisotropy could not be detected below this apparent threshold shear. The threshold was characterized by a relaxation time since anisotropy was detected only after several minutes of shearing. In contrast, the anisotropy was apparent immediately the shear was applied at the higher shears. The data were analyzed based on the assumption that the micelles behave as rigid rods. Estimates of the radii and length under shear are given. Polydispersity in rod length is discussed, and we argue that it contributes significantly to the scattering patterns.
Similar content being viewed by others
References
R. M. Bain and A. J. Hyde,Faraday Symp. Chem. Soc. 5:145 (1971).
H. Rehage and H. Hofmann,Faraday Disc. Chem. Soc. 76:363 (1983).
I. Wunderlich, H. Hofmann, and H. Rehage,Rheol. Acta 26:532 (1987).
J. B. Hayter and J. Penfold,J. Phys. Chem. 88:4589 (1984).
J. Kalus, S.-H. Chen, H. Hoffmann, G. Neubauer, P. Lindner, and H. Thurn,J. Appl. Cryst. 21:777 (1988), and references therein.
H. J. M. Hanley, G. C. Straty, and F. Tsvetkov,Langmuir 10:3362 (1994).
G. C. Straty,NIST J. Res. 94:259 (1989); G. C. Straty, H. J. M. Hanley, and C. J. Glinka.J. Stat. Phys. 62:1015 (1991).
S.-H. Chen,Ann. Rev. Phys. Chem. 37:351 (1956).
H. C. Van de Hulst,Light Scattering by Simili Particles (Wiley, New York, 1957);
A. Guinier and G. Fourmet,Small-Angle Scattering of N=Rays (Wiley, New York, 1955).
B. J. Berne and R. Pecora,Dynamic Light Scattering (Wiley, New York, 1976).
J. Penfold, J. Appl. Cryst.21:770 (1988).
P. S. Goyal, R. Chakravarthy, B. A. Dasannacharya, J. A. E. Desa, and V. K. Kelkar,Physica B 156:471 (1989).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Lin, M.Y., Hanley, H.J.M., Straty, G.C. et al. A small-angle neutron scattering (SANS) study of worm-like micelles under shear. Int J Thermophys 15, 1169–1178 (1994). https://doi.org/10.1007/BF01458825
Issue Date:
DOI: https://doi.org/10.1007/BF01458825