TY - JOUR
T1 - Modes of Interaction in Binary Blends of Hydrophobic Polyethers and Imidazolium Bis(trifluoromethylsulfonyl)imide Ionic Liquids
AU - Bentley, Caitlin L.
AU - Chwatko, Malgorzata
AU - Wheatle, Bill K.
AU - Burkey, Aaron A.
AU - Helenic, Alysha
AU - Morales-Collazo, Oscar
AU - Ganesan, Venkat
AU - Lynd, Nathaniel A.
AU - Brennecke, Joan F.
N1 - Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/8/11
Y1 - 2020/8/11
N2 - Lower critical solution behavior in binary blends of hydrophobic polyethers with 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([hmim][Tf2N]) exhibited a difference in lower critical solution temperature (LCST) greater than 80 °C between structurally homologous poly(isopropyl glycidyl ether) (PiPGE) and poly(n-butyl glycidyl ether) (PnBGE). Replacement of the acidic hydrogen on the imidazolium ring with a methyl group (i.e., 2,3-dimethyl-1-hexyl-imidazolium bis(trifluoromethylsulfonyl)imide ([hmmim][Tf2N])) significantly reduced the LCST of both the PnBGE/ionic liquid (IL) mixture and the PiPGE/IL mixture. Differing degrees of hydrogen bonding between the polymer and the cation cannot alone explain the observed behavior. Similar hydrogen bonding between the [hmim]+ cation and both polymers from molecular dynamics simulations was consistent with this conclusion. However, stronger [hmim]+ cation tail/polymer alkyl side-chain interactions for PnBGE, with consequently stronger cation/anion interactions, point to solvophobic interactions as the basis for the large LCST difference between the PnBGE/[hmim][Tf2N] and PiPGE/[hmim][Tf2N] blends.
AB - Lower critical solution behavior in binary blends of hydrophobic polyethers with 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([hmim][Tf2N]) exhibited a difference in lower critical solution temperature (LCST) greater than 80 °C between structurally homologous poly(isopropyl glycidyl ether) (PiPGE) and poly(n-butyl glycidyl ether) (PnBGE). Replacement of the acidic hydrogen on the imidazolium ring with a methyl group (i.e., 2,3-dimethyl-1-hexyl-imidazolium bis(trifluoromethylsulfonyl)imide ([hmmim][Tf2N])) significantly reduced the LCST of both the PnBGE/ionic liquid (IL) mixture and the PiPGE/IL mixture. Differing degrees of hydrogen bonding between the polymer and the cation cannot alone explain the observed behavior. Similar hydrogen bonding between the [hmim]+ cation and both polymers from molecular dynamics simulations was consistent with this conclusion. However, stronger [hmim]+ cation tail/polymer alkyl side-chain interactions for PnBGE, with consequently stronger cation/anion interactions, point to solvophobic interactions as the basis for the large LCST difference between the PnBGE/[hmim][Tf2N] and PiPGE/[hmim][Tf2N] blends.
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U2 - 10.1021/acs.macromol.0c01155
DO - 10.1021/acs.macromol.0c01155
M3 - Article
AN - SCOPUS:85089195493
SN - 0024-9297
VL - 53
SP - 6519
EP - 6528
JO - Macromolecules
JF - Macromolecules
IS - 15
ER -