Structures of Defects and Interfaces in Block Copolymer Materials [NSF Project]

The detailed structure of defects in soft materials like polymers has received relatively little attention compared to the vast literature on defects in hard crystalline materials (metals, ceramics and semiconductors), where high-resolution electron microscopy and other techniques have quantitatively imaged the new arrangements of the atoms caused by the various kinds of defects, thus enabling a very detailed understanding of the key role of surface, line, and point defects on controlling important material properties such as mechanical strength and electrical conductivity. In this lab, current research provides valuable data for comparison to theoretical simulations of the morphology of microdomain interface morphology in A-B diblock copolymers where the interplay of minimization of interfacial area between the A and B domains vs. chain stretching within the respective domains controls the shape of the interface. Additionally, we will extend and verify microscopy techniques to explore the 3D nature of grain boundary and line defects that can frequently occur in technologically important diblock structures and can limit their performance.