Stress Chain Analysis for an ABA Triblock Copolymer Using Principal Component Scores.

Researchers characterize the mechanical properties of ABA triblock copolymers by structures such as chain conformation. During elongation, bridge chains are stretched and act as a stress chain. Some loop chains also act as a stress chain because of the transmission of stress through an entanglement of loop chains. The stress chain, including the entangled loop chains, in an ABA triblock copolymer that exhibits a body-centered cubic structure was analyzed by principal component analysis (PCA), using the physical data for the B block obtained by coarse-grained molecular dynamics simulations. Local deformation of the A domains caused by the stress chains was also analyzed by PCA of the A block. The dynamics of the stress chain strongly corresponded to the recombination of the A domains; shrinkage because of domain breakage, replacement of stress chains, and biased stress distribution as well as its time dependence were observed.