Unimer micelle domains

The extent of the restriction on the mobility of an azobenzene moiety covalently incorporated into higher-order unimer micelles, monitored by photoisomerization and thermal back isomerization rates, is much more pronounced in cyclododecyl domains than in dodecyl domains, which can be related to a difference in the mobility of these aliphatic hydrophobes in the microdomains (52). Cyclododecane is a rigid molecule with much less conformational freedom than dodecane because of its cyclic structure. The latter is a flexible chain that can adopt a variety of conformations. Therefore, cyclododecyl groups may be more tightly associated than dodecyl groups and form a more rigid hydrophobic microdomain. 

The extremely long-lived ZnTPP triplets in cyclododecyl domains in the unimer micelle facilitate electron transfer reaction to electron acceptors. 

Because of the unusually long lifetime of the ZnTPP triplets in the Cd domain, the ZnTPP in the unimer micelle emits phosphorescence and E-type delayed fluorescence in aqueous solution at ordinary or higher temperatures [81-83]. This is an unusual phenomenon for Zn—porphyrins. The reference copolymer does not emit such delayed fluorescence and phosphorescence in aqueous solution at room temperature. The delayed emissions show a characteristic temperature dependence with increasing temperature, the delayed fluorescence increases, whereas the phosphorescence decreases (Fig. 15). Analysis of the temperature-dependence data shows that the delayed fluorescence is due to the thermal activation of the triplet-excited state back up to the singlet-excited state. 

The initial concentration and the lifetime of the porphyrin cation radical are strongly dependent on the type of hydrophobes in the unimer micelle. Similar differences in the extent of the protection of chromophores in the La and Cd domains were observed with pyrene and azobenzene moieties, and these differences were attributed to the difference in the local mobility... 

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