J. Phys. IV France
Volume 03, Numéro C8, Décembre 1993
IX International Conference on Small Angle Scattering
Page(s) C8-117 - C8-127
IX International Conference on Small Angle Scattering

J. Phys. IV France 03 (1993) C8-117-C8-127

DOI: 10.1051/jp4:1993822

Measurement and interpretation of counterion distributions around cylindrical micelles

S.-L. CHANG1, C.-Y. KU2, S.-H. CHEN2 and J.S. LIN3

1  Department of Nuclear Science, National Tsing-Hua University, Taiwan, R.O.C.
2  Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A.
3  Solid State Division, Oak Ridge National Laboratory, Oak Ridge, TN, U.S.A.

Radial distributions of heavy monovalent counterions around cylindrical micelles are measured directly using a small angle x-ray scattering. For the purpose of the analysis, the shape and size of the micelles are determined separately by a small angle neutron scattering. The micelles we used are formed by a comb-shaped copolymer poly-(1-octadecene-co-maleic anhydride), abbreviated as PODMA in aqueous solutions neutralized by cesium hydro-oxides. The results are used to critically test the validity of solutions of non-linear Poisson-Boltzmann (PB) equation in the cell model to predict the radial distributions of monovalent counterions. The accuracy of the solutions of the non-lineaar PB equation for different magnitudes of linear charge density parameter is checked against Monte Carlo simulations. For comparison, we also show results of a similar experiment and analysis done for the counterion distributions around persistent length DNA in solution.

© EDP Sciences 1993