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Baek, Jong-Beom
Center for Dimension-Controllable Organic Frameworks
Research Interests
  • Covalent Organic Frameworks (COFs), Carbon Nanotubes(CNTs), graphene, Energy Conversion and Storage

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Macromolecular dumbbells: synthesis and photophysical properties of hyperbranched poly(etherketone)-b-polybenzobisthiazole-b-hyperbranched poly(etherketone) ABA triblock copolymers

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dc.contributor.author Baek, Jong-Beom ko
dc.contributor.author Lyons, Christopher B. ko
dc.contributor.author Tan, Loon-Seng ko
dc.date.available 2014-04-09T08:24:16Z -
dc.date.created 2013-06-17 ko
dc.date.issued 2009-06 ko
dc.identifier.citation JOURNAL OF MATERIALS CHEMISTRY, v.19, no.24, pp.4172 - 4182 ko
dc.identifier.issn 0959-9428 ko
dc.identifier.uri https://scholarworks.unist.ac.kr/handle/201301/2597 -
dc.description.abstract A series of hyperbranched poly(etherketone)-b-poly(benzobisthiazole)-b-hyperbranched poly(etherketone) triblock copolymers were synthesized. Two different types of hyperbranched poly(etherketone)s (PEKs) were utilized as dendritic A-block units and carboxylic acid-terminated polybenzobisthiazoles (PBZTs) with two different molecular weights as a conjugated, optically responsive, rigid-rod B-block units to afford dumbbell-shaped ABA triblock copolymers. Although all dumbbell-shaped samples are soluble in strong acids such as trifluoroacetic acid (TFA), methanesulfonic acid (MSA), trifluoromethanesulfonic acid (TFMSA) and sulfuric acid, only phenoxy-terminated dumbbell shaped triblock copolymers (3a and 3b) were soluble in common polar aprotic solvents such as NMP, DMF, DMAc and DMSO. Their solubility in common organic solvents was apparently a consequence arising from the obstruction of the close packing of PBZT components by the bulky dendritic PEK ends. A very surprising and interesting observation was made when the 3a and 3b solutions in NMP were placed under room light for 24 h: all major absorption peaks became featureless and blue-shifted. This photochromism was investigated by static and dynamic UV-absorption and fluorescence spectroscopy under various conditions. Although the response time was quite long, it could be controlled as a function of excitation wavelength, light intensity, and solvent viscosity and/or polarity. We propose that the origin of observed spectral changes is caused by the change in conjugation lengths of PBZT in the dumbbell-shaped ABA triblock copolymers. ko
dc.description.statementofresponsibility close -
dc.language 영어 ko
dc.publisher ROYAL SOC CHEMISTRY ko
dc.title Macromolecular dumbbells: synthesis and photophysical properties of hyperbranched poly(etherketone)-b-polybenzobisthiazole-b-hyperbranched poly(etherketone) ABA triblock copolymers ko
dc.type ARTICLE ko
dc.identifier.scopusid 2-s2.0-67149141759 ko
dc.identifier.wosid 000266797500017 ko
dc.type.rims ART ko
dc.description.wostc 6 *
dc.description.scopustc 6 *
dc.date.tcdate 2015-02-28 *
dc.date.scptcdate 2014-08-25 *
dc.identifier.doi 10.1039/b901483g ko
dc.identifier.url http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=67149141759 ko
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