The relationship between ionic conductivity, morphology, and rheological properties of polystyrene-block-poly(ethylene oxide) copolymers (SEO) doped with a lithium salt, Li[N(SO2CF3)2], is elucidated. We focus on lamellar samples with poly(ethylene oxide) (PEO) volume fractions, φ, ranging from 0.38 to 0.55, and PEO block molecular weights, M PEO, ranging from 16 to 98 kg/mol. The low-frequency storage modulus (G‘) at 90 °C increases with increasing M PEO from about 4 × 105 to 5 × 107 Pa. Surprisingly, the conductivity of the SEO/salt mixtures with the molar ratio of Li to ethylene oxide moieties of 0.02 σ, also increases with increasing M PEO, from 6.2 × 10-5 to 3.6 × 10-4 S/cm at 90 °C. We compare σ with the conductivity of pure PEO/salt mixtures, σPEO, and find that σ/[φσPEO] of our highest molecular weight sample is close to 0.67, the theoretical upper limit for transport through randomly oriented lamellar grains.

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Micelles of cetyltrimethylammonium bromide (CTAB), when doped with increasing levels of 4-ethylphenol, show microstructural transitions from spherical micelles to elongated wormlike micelles, disks, and subsequently to globular and then to tubular vesicles. Wormlike micelles are observed at a dopant-to-CTAB molar ratio of 1:3. At higher dopant ratios (1:1), globular vesicles are observed which transition to tubular vesicles when the dopant becomes the predominant species at a ratio of 3:1. These transitions are reflected in small-angle neutron scattering analysis and, interestingly, can be directly observed through cryo-transmission electron microscopy. The para-substituted phenol is interfacially active and modulates interfacial curvature of the micelles. The observations of microstructure modifications have relevance to the synthesis of mesoporous materials using CTAB as the template.