Characterizing semiflexible network structure of wormlike micelles by dynamic techniques†

Understanding the structure–property relationships of semiflexible polymer networks is essential for their rational design and application across diverse fields. While classical static structural characterizations have been widely used, dynamic investigations also provide a powerful approach to analyzing these networks across multiple hierarchical levels in both time and length scales. This study presents a comprehensive methodology to dynamically determine key structural parameters in semiflexible polymer networks, characterizing time, length, volume, and molecular weight of unit segments at their respective hierarchical levels, such as Kuhn monomers, correlation blobs, and network strands. A wormlike micellar solution of sodium dodecyl sulfate and aluminum nitrate was used as a model system representing semiflexible polymers with a large Kuhn length. By combining dynamic experimental techniques, including dynamic light scattering, macrorheology, and microrheology, crucial structural information was obtained. Integrating information derived from the characteristic parameters successfully revealed the hierarchical network structure of the wormlike micelles, with results validated against static light scattering measurements. Notably, this study effectively utilizes the complex viscoelastic modulus obtained through microrheology, which has received limited attention in the literature. This approach holds potential applicability to a wide range of semiflexible polymer networks.