Fully Liquid-Crystalline ABA Triblock Copolymer of Fluorinated Side-Chain Liquid-Crystalline A Block and Main-Chain Liquid-Crystalline B Block: Higher Order Structure in Bulk and Thin Film States

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• 作者：Ryohei Ishige ; Noboru Ohta ; Hiroki Ogawa ; Masatoshi Tokita ; Atsushi Takahara
• 刊名：Macromolecules
• 出版年：2016
• 出版时间：August 23, 2016
• 年：2016
• 卷：49
• 期：16
• 页码：6061-6074
• 全文大小：970K
• 年卷期：0
• ISSN：1520-5835

文摘

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 (φ_A) 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 φ_A is 0.11, matching of the mesogen orientation in the A and B blocks dominates the main-chain orientation, whereas when φ_A 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 φ_A = 0.70 was completely perpendicular to the Si substrate without surface modification or solvent annealing.