End-Coupling Synthesis of Poly (phenylene vinylene)-b-Poly2-vinyl pyridine) Rod-Coil Block Copolymers and Theirelf-Assembling Behavior
Date Issued
2008
Date
2008
Author(s)
Huang, Shih-Hau
Abstract
Recently, the self-assembling behavior of rod-coil block copolymers has been rapidly explored. In the thesis, an aldehyde-terminated poly(phenylene vinylene) (PPV) wasynthesized by Siegrist polycondensation method, and the polymer had a number average molecular weight of 5000g/mol with narrow polydispersity. In addition, a monodispersedomopolymer living anion of poly(2-vinyl pyridine) (P2VP) was synthesized via anionic polymerization using sec-butyllithium as an initiator. Block copolymers of PPV-b-P2VP were synthesized by a nucleophilic addition reaction between P2VP living anion and aldehyde-terminated PPV. Five PPV-b-P2VP block copolymers with different PPV/P2VP molar ratio were successfully synthesized with high yield (>90%). The synthesized PPV-b-P2VPs were characterized by using various techniques including gel permeation chromatography (GPC), UV-VIS, photoluminescence (PL), TGAthermogravimetric analysis) and differential scanning calorimetry (DSC). Furthermore, the self-assembling behavior of block copolymers was investigated by using TEM. Different microphase structures, e.g. lamellae, cylinders, and spheres were observed for differentompositions of the copolymers. In the end, we used the wide angle X-ray scattering technique to study the crystalline structure of PPV in the PPV-P2VP nanostructure. It was found that the crystallinity of PPV decreases with increasing P2VP molecular weight.
Subjects
rod-coil block copolymer
poly(phenylene vinylene)
poly(2-vinyl pyridine)
anionic polymerization
end-coupling reaction
self-assembling behavior
Type
thesis
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