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Abstract: Micelle formation was studied for "nonamphiphilic" diblock copolymers consisting entirely of solvophilic polymer blocks. Poly(vinylphenol)-block-polystyrene (PVPh-b-PSt) showed no self-assembly in 1,4-dioxane, a nonselective solvent. This nonamphiphilic diblock copolymer formed spherical micelles in the nonselective solvent in the presence of α,ω-diamine such as 1,4-butanediamine, hexamethylenediamine, and ethylenediamine. Steric hindrance at the amino groups and too long chains between the amino groups prevented the copolymer from aggregating. 1H NMR revealed that the micellization occurred by hydrogen bond cross-linking between the PVPh blocks via α,ω-diamine. The critical micelle concentration was determined by the diamine concentration, rather than by the copolymer concentration. The micelles were thermally unstable and dissociated into unimers by increasing the temperature, however, the micelles were completely reconstructed by decreasing the temperature. This dissociation-reconstruction of the micelles was perfectly controlled by the variation in temperature. The self-assembly of the nonamphiphilic copolymers by the α,ω-diamine created a great variety of micelles. The syntheses of crew-cut micelles, random block copolymer micelles, and the micelles with dyes and/or UV absorbents at their cores and/or coronas from the nonamphiphilic copolymers are also described.
Key words: nonamphiphilic copolymers, micelle formation, α,ω-diamine, hydrogen bond cross-linking, nanodyes
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