LAUSR

Abstract We here shed light on effects of the A domain cross-linking for the physical properties, especially for the B middle block segmental motion, of ABA triblock copolymers with a soft B block and A glassy end blocks bearing photo cross-linkable moieties. For extraction of the intrinsic effects of cross-linking, we utilize room temperature photo cross-linking. Scattering measurements and model analysis finely confirm that the photo cross-linking proceeds without any influences on the morphology. Unexpectedly, the cross-linking of A domain affects not only the segmental motion of A block but also the B block segmental motion. Concretely, DSC and rheological measurements revealed that Tg (or α-relaxation temperature) of the B soft block decreased (ΔTg ~ 4 °C) and the apparent activation energy (Ea) of the B soft segmental motion increased (ΔEa ~90 kJ mol−1), which were discussed with assuming the rigidity change of B segment in the interfacial mixed layer.