Synthesis and hierarchical self-assembly of rod-rod block copolymers via click chemistry between mesogen-jacketed liquid crystalline polymers and helical polypeptides

Qing Han Zhou, Ju Kuan Zheng, Zhihao Shen, Xing He Fan, Xiao Fang Chen, Qi Feng Zhou

Research output: Contribution to journalArticlepeer-review

51 Scopus citations

Abstract

A series of novel rod-rod diblock copolymers containing poly{2,5-bis[(4-methoxyphenyl)-oxycarbonyl]styrene} (PMPCS) and poly(γ-benzyl-L-glutamate) (PBLG) were synthesized by click chemistry from alkyne-and azide-functionalized homopolymers. The α-alkyne PMPCS homopolymers were synthesized by copper-mediated atom transfer radical polymerization with a bromine-containing α-alkyne bifunctional initiator, and α-azido PBLG homopolymers were synthesized by ring-opening polymerization of γ-benzyl-L-glutamate N-carboxyanhydride with an amino-containing α-azide initiator. The molecular structures of the rod-rod block copolymers were confirmed by 1H NMR spectroscopy, Fourier transform infrared spectroscopy, and gel permeation chromatography analysis. The self-assembling behavior of the rod-rod block copolymers in bulk was investigated using differential scanning calorimetry, polarized light microscopy, wide-angle X-ray diffraction, and transmission electron microscopy techniques. A lamellar structure was observed with fPBLG of ∼0.50, in which PMPCS was in a columnar nematic phase and PBLG assignedto a hexagonally packed-cylinder structure (ΦH). Accordingto the TEM micrographs and simulated lengths of the copolymers, a stacked bilayer structure in a hexagon in lamella morphology for the selfassembly of the rod-rod block copolymers was proposed. Finally, by increasing fPBLG to ∼0.69, a microphase-separated hexagon in cylinder morphology was found, in which PMPCS formed the core of the cylinders surrounded by PBLG in ΦH phase and both rods were in an interdigitated packing.

Original languageEnglish (US)
Pages (from-to)5637-5646
Number of pages10
JournalMacromolecules
Volume43
Issue number13
DOIs
StatePublished - Jul 13 2010

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