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Mixed (ionic and electronic) conductive solid polymer matrix. Synthesis and characterization of homopolymers of 3‐(2,5,8,11,14,17,20,23‐octaoxyhexadodecyl)thiophene and copolymers with 3‐methylthiophene
Author(s) -
Burke, Jr. L. Michael,
Khan Ishrat M.
Publication year - 2000
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(20001101)201:17<2228::aid-macp2228>3.0.co;2-x
Subject(s) - macromonomer , thiophene , ionic conductivity , ethylene oxide , glass transition , copolymer , materials science , polymer chemistry , ionic bonding , conductive polymer , lithium (medication) , polymer , chemistry , organic chemistry , ion , electrode , composite material , medicine , electrolyte , endocrinology
The macromonomer, 3‐(2,5,8,11,14,17,20,23‐octaoxyhexadodecyl)thiophene, abbreviated as (3‐OHDT), was synthesized. The macromonomer has a glass transition temperature of –77°C, which corresponds to the soft oligooxyethylene side chain attached to the thiophene. The homopolymer, poly[3‐(2,5,8,11,14,17,20,23‐octaoxyhexadodecyl)thiophene], abbreviated to P[3‐(OHDT)], has been synthesized via oxidative coupling of the macromonomer using FeCl 3 . Two distinct glass transition temperatures are observed for the homopolymer. The T g at –47°C corresponds to the soft oligooxyethylene phase and the T g value at 72°C corresponds to the hard thiophene backbone. The homopolymer P[3‐(OHDT)] can be doped with LiClO 4 and I 2 to generate ionic and electronic conductive phases, respectively. For the P[3‐(OHDT)]/LiClO 4 system, with an ethylene oxide to lithium mole ratio of 8 : 1, an ionic conductivity value of 1.7×10 –6 S cm –1 is observed at 25°C. The room temperature electronic conductivity of P[3‐(OHDT)]/doped with I 2 is 3.5x10 –4 S cm –1 . Several random copolymers of 3‐methylthiophene and 3‐(2,5,8,11,14,17,20,23‐octaoxyhexadodecyl)thiophene were also synthesized. Depending on the copolymer composition, glass transition temperatures ranged from 67°C to 76°C, the higher glass transition temperature corresponding to higher 3‐methylthiophene content. The copolymers may be appropriately doped to generate conductive matrices, with a maximum ionic conductivity (ethylene oxide/Li + mole ratio of 8 : 1) of 1.0×10 –7 S cm –1 and electronic conductivity around 6.7×10 –1 S cm –1 at 25°C.