Effects of compositional asymmetry in phase behavior of ABA triblock copolymer melts from Monte Carlo simulation
Faculty of Physics, A. Mickiewicz University, ul. Umultowska 85, 61-614, Poznan, Poland
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Accepted: 15 November 2010
Published online: 2 December 2010
We simulate ABA triblock copolymer melts using a lattice Monte Carlo method, known as cooperative motion algorithm, probing various degrees of compositional asymmetry. Selected order-disorder transition lines are determined in terms of the segment incompatibility, quantified by product N , and the triblock asymmetry parameters, and . We correlate the results of the simulation with the self-consistent field theory and an experimental study of polyisoprene-polystyrene-polyisoprene triblock melt by Hamersky and coworkers. In particular, we confirm the mean-field prediction that for highly asymmetric triblocks the short A -block is localized in the middle of the B -domain due to an entropic advantage. This results in the middle block relaxation and is consistent with the experimental data indicating that as the relatively short A -blocks are grown into AB diblock, from the B -block side, the order-disorder transition temperature is considerably depressed.
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2010