Increasing block copolymer dispersity leads to more uniform micelles

Synthetic polymers posses some inherent dispersity in their length due to the mechanism of the underlying polymerization reaction. Since nearly every property of the polymers depend strongly on the length of the chain, it is expected that the polymer chain dispersity effects different structural, dynamic and their self-assembly properties in the solution as well as in the melt conditions. In this work we investigate the effect of amphiphilic diblock copolymer chain length dispersity on the size distribution of the spherical micelles formed by them in the solution. Using self-consistent field theory calculations, we show that the monodisperse diblock copolymers form micelles of different sizes in the solution, whereas polydisperse diblock copolymers form micelles which are uniform in size. We attribute this to the fact that the packing of the solvophobic monomers in the micellar core can be optimized if the constituent polymers have different length.

German Science Foundation - SFB 1066 (Project Q1), SFB 146 (Project C1).