We have controlled the structure of self –assembled systems by introducing charges (charge effect) and polymeric tails (steric effects) on a spherical –cylindrical shape of nonionic surfactant micelles. Furthermore, the effect of a phospholipid (DL-a-phosphatidycholine Dimyristol: DMPC), which forms an extended flat bilayer aggregate (nearly zero spontaneous curvature), on the shape of nonionic surfactant micelle (penta-ethyleneglycol mono n-dodecyl ether: C12E5 ) has been studied in terms of an aggregation number, critical micellization concentration (CMC), second virial coefficient (A2), and hydrodynamic diameter (DH) by laser light scattering. The aggregation number and critical micellization concentration increase as adding a phospholipid molecule. Based on the values of CMC, the total free energy per micelle of C12E5 /DMPC mixtures is estimated. The free energy per micelle of C12E5 /DMPC mixtures decreases as DMPC is added. This is consistent with the decrease of A2 and the strong hydrophobicity of DMPC compared with C12E5. The average contour length, the diffusion coefficient, and the end cap energy of mixed micelle are estimated based on the CMC and molecular specific volumes of the moiety. The end-cap energy and the average contour length of the mixed micelle increase as adding DMPC, which is also reasonable when considering the molecular structure of DMPC. The decreasing in estimated diffusion coefficient with one dimensional growth model from static light scattering measurements are in excellent agreement with diffusion coefficients obtained from dynamic light scattering measurements. Furthermore, the clear evidence of topological transition has been shown for the first time by light scattering and viscometry. The experimental study is compared with a recent theoretical study. In addition, I’ll show the small angle neutron scattering results of the charge effects on the nonionic micellar systems.
Finally, I’ll introduce some of the current activities in the soft matter physics group and the biomolecular self-assembling nanomaterials (B-SAN)center.