Fully liquid-crystalline (LC) ABA-type triblock copolymers were synthesized by atom transfer radical polymerization; the A block was a fluorinated side-chain LC polymer, PFA-C8, and the B block was a main-chain LC polyester, BB-5(3-Me). The volume fraction of the A block (ψA) was 0.11-0.70, and the B block had a constant molecular weight. Nanometer-scale segregated structures in the bulk and thin film states were investigated by synchrotron X-ray diffraction (XRD) in transmission and grazing-incidence (GI) geometries to examine the effect of competition between the LC orientation and polymer chain dimensions on the morphology. When ψA is 0.11, matching of the mesogen orientation in the A and B blocks dominates the main-chain orientation, whereas when ψA exceeds 0.28, matching of the lateral dimensions of the A and B blocks dominates the mesogen orientation, although all the polymers showed lamellar structure before isotropization of BB-5(3-Me). GI-XRD revealed that the lamellar structure in the thin film with ψA = 0.70 was completely perpendicular to the Si substrate without surface modification or solvent annealing.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry