Monte carlo investigations of dense copolymer systems II, properties of ABA triblocks

In the present article we give a detailed analysis of ABA triblock copolyme rs in a selective solvent that is a good one for the outer blocks and a the ta solvent for the inner one. A lattice model is used for the investigation s and the concentration ranges from a volume fraction phi=0 up to phi=0.8. The results are compared to the behavior of the constituent homopolymers, i .e., homopolymers in athermal (AAA) and theta solvent (BBB). In the limit p hi --> 0 the concentration dependence of properties of the whole chain as w ell as properties of individual blocks, may be deduced from pair-data with excellent precision for all systems under consideration. For large concentr ations mean square dimensions of ABA markedly exceed that of AAA or BBB, re spectively, due to microphase separation which becomes evident for concentr ations larger than phi approximate to 0.4 which corresponds to the point wh ere intermolecular and intramolecular interactions are equally important. ( C) 2000 American Institute of Physics. [S0021-9606(99)51648-6].