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Electrochemical and Optical Properties of Novel Poly(3‐substituted‐2,2′‐bithiophene)s
Author(s) -
Miao Ping,
Zhang ChunYan,
Chan Hardy S. O.,
Ng SiuChoon
Publication year - 2001
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20010101)202:1<1::aid-macp1>3.0.co;2-l
Subject(s) - materials science , monomer , polymer , boron trifluoride , polymer chemistry , electrochemistry , electrode , chemistry , organic chemistry , composite material , catalysis
The electrochemical and optical properties of poly(3‐substituted‐2,2′‐bithiophene)s with bromo, alkyl, alkoxy and alkylthio pendants obtained by electrochemical polymerisation were investigated. As 3‐alkylthiothiophenes, 3‐alkylthio‐2,2′‐bithiophenes cannot be electropolymerised although the polymer can be successfully generated via a chemical oxidative approach. Other monomers were successfully electropolymerised to afford uniform polymer films on the anodic electrodes by adopting either Bu 4 NBF 4 —CH 3 CN or boron trifluoride diethyl etherate (BF 3 —OEt 2 ) as the electrolytic media. These two media exhibit contrasting effects on the film formation behaviour and optoelectronic properties in some of these polybithiophenes with different pendants. The oxidation potentials of monomers in Bu 4 NBF 4 —CH 3 CN follow the trend: 3‐methoxy‐2,2′‐bithiophenes < 3‐octylthio‐2,2′‐bithiophenes < 2,2′‐bithiophenes < 3‐octyl‐2,2′‐bithiophenes < 3‐bromo‐2,2′‐bithiophenes while those of the polymers are poly(3‐methoxy‐2,2′‐bithiophene)s < poly(3‐octyl‐2,2′‐bithiophene)s < poly(2,2′‐bithiophene)s < poly(3‐bromo‐2,2′‐bithiophene)s. However, in BF 3 —OEt 2 the trend of oxidation potentials for monomers is 3‐octylthio‐2,2′‐bithiophenes < 2,2′‐bithiophenes < 3‐bromo‐2,2′‐bithiophenes < 3‐octyl‐2,2′‐bithiophenes < 3‐methoxy‐2,2′‐bithiophenes while that for polymers is poly(3‐octyl‐2,2′‐bithiophenes) < poly(3‐methoxy‐2,2′‐bithiophenes) < poly(2,2′‐bithiophenes) < poly (3‐bromo‐2,2′‐bithiophenes). The facile and stable p‐ and n‐dopability of poly(3‐alkyl‐2,2′‐bithiophene) was also investigated.