Interaction of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide with an electrospun PVdF membrane: Temperature dependence of the concentration of the anion conformers.
We measured the temperature dependence of the infrared absorption spectrum of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PY R14-TFSI) between 160 and 330 K, through all the phase transitions presented by this compound. The comparison of the experimental spectra with the calculated vibration modes of different conformers of the ions composing the ionic liquid allowed to detect the presence of both conformers of TFSI in the liquid, supercooled, and glass phases, while only the trans-conformer is retained in both solid phases. When the ionic liquid swells a polyvinylidenefluoride (PVdF) electrospun membrane, the cis-rotamer is detected in all phases, since the interaction between the polymer and the ionic liquid inhibits the complete transformation of TFSI into the trans-conformer in the solid phases. Computational results confirm that in the presence of a PVdF chain, cis-TFSI becomes the lowest energy conformer. Therefore, the interaction with the polymer alters the physical properties of the ionic liquid.
CNR-ISC, U.O.S. La Sapienza, Piazzale A. Moro 5, 00185 Roma, Italy.
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Vitucci
CNR-ISC, U.O.S. La Sapienza, Piazzale A. Moro 5, 00185 Roma, Italy.
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Palumbo
Physics Department, Sapienza University of Rome, Piazzale A. Moro 5, 00185 Roma, Italy.
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Trequattrini
Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France.
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Brubach
Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France.
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Roy
Pharmacy Department, University "G. d'Annunzio," Via dei Vestini 31, 66100 Chieti, Italy.
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Meschini
Pharmacy Department, University "G. d'Annunzio," Via dei Vestini 31, 66100 Chieti, Italy.
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Croce
CNR-ISC, U.O.S. La Sapienza, Piazzale A. Moro 5, 00185 Roma, Italy.
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Paolone
D000838:Anions; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D007094:Imides / Q000737:chemistry*; D008968:Molecular Conformation; D013055:Spectrophotometry, Infrared; D013696:Temperature
D000838:Anions; D006845:Hydrocarbons, Fluorinated; D007094:Imides; C575299:bis(trifluoromethanesulfonyl)imide