Mechanochemical Activation in Nanostructured Triblock Copolymers: A Computational Study

Force-driven chemical reactions have emerged as an attractive platform for diverse applications in polymeric materials. However, the microscopic chain conformations and topologies necessary for efficiently transducing macroscopic forces to the molecular scale are not well-understood. In this talk, we demonstrate the importance of polymer conformations and nano-scale morphology for force-responsive copolymers by investigating the impact of network-like topology on mechanochemical activation in self-assembled triblock copolymers. Using a simple coarse-grained model, we find that activation during tensile deformation depends strongly on both the polymer composition and chain conformation in these materials, with activation requiring higher stress in materials with a higher glassy block content, and most activation occurring in the tie chains connecting different glassy domains. Additionally, we observe a spatial pattern of activation which appears to be tied to distortion of the self-assembled morphology. Higher activation is observed in the tips of the chevrons formed during deformation of lamellar samples, as well as in the centers between the cylinders in the cylindrical morphology. Our work shows that changes in the network-like topology of chains in different morphologies significantly impact mechanochemical activation efficiencies in these materials, suggesting that this area will be a fruitful avenue for further research.