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Dynamic Chain Exchange of Amphiphilic Alternating/Random Copolymer Micelles Promoted by Structural Uniformity and Flexibility

Researchers compared amphiphilic alternating and random copolymer micelles in water, finding that alternating copolymers form monodisperse multichain micelles with narrow size distributions. Kinetic studies using fluorescence energy transfer showed that chain exchange between alternating micelles occurs faster than with random copolymers. The exchange rate increases with higher aggregation numbers, temperature, and polymer concentration, involving both unimer release/insertion and micelle‑collision pathways. Notably, the collision pathway becomes more dominant under concentrated, warm conditions, highlighting the role of structural uniformity and flexibility in micelle dynamics.