Chain exchange kinetics between linear ABA-type triblock copolymer micelles

A Prhashanna and SB Chen, POLYMER, 118, 22-29 (2017).

DOI: 10.1016/j.polymer.2017.04.049

Chain exchange kinetics between triblock block copolymers of ABA-type with end block being soluble in solvent is investigated using dissipative particle dynamics simulations for the first time. In such micelles, the polymer conformation is believed to play an important role. Our simulations find that a majority of polymer chains take loop (bend) conformations within the micelle, and unimer expulsion is the dominant mechanism for exchange. The chain exchange follows a first- order kinetic process, for which the characteristic time T increases with both core and corona block lengths, showing a qualitative agreement with the literature. While the strong effect of core block length is due to an increase in activation energy, the marginal effect of corona block length is attributable to the re-insertion of an escaping chain into the same micelle. Re-insertion is favored because of greater resistance for a chain to escape a thicker corona. (C) 2017 Elsevier Ltd. All rights reserved.

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