For diblockcopolymers of polybutadiene-poly(ethyleneoxide) (PB-PEO) type, water is a selective solvent. In dependence of the length of both blocks and the block length ratio, these polymers form a multitude of self-assembled structures in solution. In the present work scattering methods are used to investigate the water-soluble polymer ${\mathrm{PB}}_{125}\text{−}{\mathrm{PEO}}_{155}$. It is found to form long rodlike micelles, which are characterized with respect to the aggregate length $L$, the cross sectional radius $R_{\mathrm{CS}}$, the radial scattering length density profile $\sigma \left(r\right)$, and the radial aggregation number $N_{\mathrm{rad}}$. Model-independent as well as model-based approaches are used for the scattering data analysis. From dynamic light scattering (DLS) and static light scattering (SLS) experiments the weight averaged length $L_w$ of these stiff elongated aggregates is determined to $L_w=350\mathrm{nm}$. Small angle neutron scattering (SANS) reveals a cross sectional radius of $R_{\mathrm{CS}}=17\mathrm{nm}$ and in combination with results from the SLS the radial aggregation number is found to be $N_{\mathrm{rad}}=70$.

• Received 29 January 2004

DOI:https://doi.org/10.1103/PhysRevE.70.041408