STATIC STRUCTURE FACTOR OF POLYMER-LIKE MICELLES - OVERALL DIMENSION,FLEXIBILITY, AND LOCAL PROPERTIES OF LECITHIN REVERSE MICELLES IN DEUTERATED ISOOCTANE

We report a systematic investigation of the static structure factor S( q,c) of polymerlike reverse micelles formed by soybean lecithin and tr ace amounts of water in deuterated isooctane using small-angle neutron scattering and static light scattering. The experimental data for dif ferent concentrations in the dilute and semidilute regime cover approx imately three decades of scattering vectors. The data have been analyz ed using polymer renormalization-group theory and a nonlinear least-sq uares fitting procedure based upon a numerical expression for the sing le chain scattering function of a wormlike chain with excluded-volume effects. Furthermore, the influence of interaction effects on the stat ic structure factor have been successfully examined within a modified random-phase approximation. Additional information on the local scale has been extracted by applying indirect Fourier transformation and squ are-root deconvolution techniques. We demonstrate that we can determin e structural properties such as the micellar cross-section profile and flexibility as well as quantitatively incorporate the influence of mi cellar growth and excluded-volume effects on S(q,c).