TY - JOUR
T1 - Imidazolium polyesters
T2 - Structure-property relationships in thermal behavior, ionic conductivity, and morphology
AU - Lee, Minjae
AU - Choi, U. Hyeok
AU - Salas-De La Cruz, David
AU - Mittal, Anuj
AU - Winey, Karen I.
AU - Colby, Ralph H.
AU - Gibson, Harry W.
PY - 2011/2/22
Y1 - 2011/2/22
N2 - New bis(ω-hydroxyalkyl)imidazolium and 1,2-bis[N-(ω- hydroxyalkyl)imidazolium]ethane salts are synthesized and characterized; most of the salts are room temperature ionic liquids. These hydroxyl end-functionalized ionic liquids are polymerized with diacid chlorides, yielding polyesters containing imidazolium cations embedded in the main chain. By X-ray scattering, four polyesters are found to be semicrystalline at room temperature: mono-imidazolium-C11-sebacate-C6 (4e), mono-imidazolium-C11-sebacate-C11 (4c), bis(imidazolium)ethane-C6-sebacate-C6 (5a), and bis(imidazolium)ethane-C11-sebacate-C11 (5c), all with hexafluorophosphate counterions. The other imidazolium polyesters, including all those with bis(trifluoromethanesulfonyl)imide (TFSI-) counterions, are amorphous at room temperature. Room temperature ionic conductivities of the mono-imidazolium polyesters (4 × 10-6 to 3 × 10 -5 S cm-1) are higher than those of the corresponding bis-imidazolium polyesters (4 × 10-9 to 8 × 10 -6 S cm-1), even though the bis-imidazolium polyesters have higher ion concentrations. Counterions affect ionic conduction significantly; all polymers with TFSI- counterions have higher ionic conductivities than the hexafluorophosphate analogs. Interestingly, the hexafluorophosphate polyester, 1,2-bis(imidazolium)ethane-C11- sebacate-C11 (5c), displays almost 400-fold higher room temperature ionic conductivity (1.6 × 10-6 S cm-1) than the 1,2-bis(imidazolium)ethane-C6-sebacate-C6 analog (5a, 4.3 × 10-9 S cm-1), attributable to the differences in the semicrystalline structure in 5c as compared to 5a. These results indicate that semicrystalline polymers may result in high ionic conductivity in a soft (low glass tranition temperature, Tg) amorphous phase and good mechanical properties of the crystalline phase. A series of di(hydroxyalkyl) imidazolium ionic liquids and main-chain imidazolium polyesters are synthesized and characterized. The structure-property relationships for thermal behavior, ionic conductivity, and X-ray scattering morphology are investigated. C 11-sebacate-C11 spacers create semicrystalline morphologies with high ionic conductivity.
AB - New bis(ω-hydroxyalkyl)imidazolium and 1,2-bis[N-(ω- hydroxyalkyl)imidazolium]ethane salts are synthesized and characterized; most of the salts are room temperature ionic liquids. These hydroxyl end-functionalized ionic liquids are polymerized with diacid chlorides, yielding polyesters containing imidazolium cations embedded in the main chain. By X-ray scattering, four polyesters are found to be semicrystalline at room temperature: mono-imidazolium-C11-sebacate-C6 (4e), mono-imidazolium-C11-sebacate-C11 (4c), bis(imidazolium)ethane-C6-sebacate-C6 (5a), and bis(imidazolium)ethane-C11-sebacate-C11 (5c), all with hexafluorophosphate counterions. The other imidazolium polyesters, including all those with bis(trifluoromethanesulfonyl)imide (TFSI-) counterions, are amorphous at room temperature. Room temperature ionic conductivities of the mono-imidazolium polyesters (4 × 10-6 to 3 × 10 -5 S cm-1) are higher than those of the corresponding bis-imidazolium polyesters (4 × 10-9 to 8 × 10 -6 S cm-1), even though the bis-imidazolium polyesters have higher ion concentrations. Counterions affect ionic conduction significantly; all polymers with TFSI- counterions have higher ionic conductivities than the hexafluorophosphate analogs. Interestingly, the hexafluorophosphate polyester, 1,2-bis(imidazolium)ethane-C11- sebacate-C11 (5c), displays almost 400-fold higher room temperature ionic conductivity (1.6 × 10-6 S cm-1) than the 1,2-bis(imidazolium)ethane-C6-sebacate-C6 analog (5a, 4.3 × 10-9 S cm-1), attributable to the differences in the semicrystalline structure in 5c as compared to 5a. These results indicate that semicrystalline polymers may result in high ionic conductivity in a soft (low glass tranition temperature, Tg) amorphous phase and good mechanical properties of the crystalline phase. A series of di(hydroxyalkyl) imidazolium ionic liquids and main-chain imidazolium polyesters are synthesized and characterized. The structure-property relationships for thermal behavior, ionic conductivity, and X-ray scattering morphology are investigated. C 11-sebacate-C11 spacers create semicrystalline morphologies with high ionic conductivity.
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U2 - 10.1002/adfm.201001878
DO - 10.1002/adfm.201001878
M3 - Article
AN - SCOPUS:79951590384
SN - 1616-301X
VL - 21
SP - 708
EP - 717
JO - Advanced Functional Materials
JF - Advanced Functional Materials
IS - 4
ER -