Morphologies, Phase Behavior, And Applications Of Precise Ion-Containing Multiblock Copoylmers

The capability of block copolymers to self-assemble into nanometer-scale ordered morphologies has greatly advanced their applications in a variety of areas of nanotechnology. To reach sub-10 nm and even smaller length scales, a deeper understanding of ordered morphologies and phase behavior in block copolymers is required. This thesis focuses on self-assembled morphologies and phase behavior of precise ion-containing multiblock copolymers, and their applications as single-ion conducting polymers. By systematically modifying the block chemistry in precise ion-containing multiblock copolymers, ordered morphologies such as layered, double gyroid, and hexagonally-packed cylinder morphologies are produced with sub-3 nm domain spacings. The morphology – conductivity relationship in these precise ion-containing multiblock copolymers reveals that the bicontinuous double gyroid morphology exhibits faster ion transport than the isotropic hexagonally-packed cylinder morphology. The phase behavior in these ion-containing polymers provides insight into the formation of ordered morphologies in bulk and thin films. The origin of microphase separation at sub-3 nm length scales is attributed to the presence of ionic groups and alternating multiblock architecture. The fundamental understanding of phase behavior in these ion-containing polymers provides criteria for designing double gyroid and other ordered morphologies in alternating multiblock copolymers. The ionic layers of precise ion-containing polyesters are selectively solvated to enhance ion transport. The ionic conductivity of solvated ionic layers is > 104 times higher than in the dried state. The increase in ionic conductivity is due to faster structural relaxation and a larger number of charge carriers in solvated ionic layers. This study provides a useful strategy to tune the ionic domains and increase the ionic conductivity of single-ion conducting polymers. A new series of precise ion-containing polyamide sulfonates are synthesized via step-growth polymerization. These polymers contain lithiated phenyl sulfonate in polar blocks that precisely alternate with a fixed number of x aliphatic carbons (x = 4, 5, 10, or 16). These precise ion-containing polyamides exhibit layered ionic aggregates with crystalline polymer backbone when x = 16. The ionic layers and crystalline polymer backbone persist at 250 °C, indicating great thermal stability. This study expands the accessible block chemistry of precise ion-containing multiblock copolymers by using step-growth polymerization.