Abstract
The miscibility and distribution of Br- and BF4 - ions of imidazolium ionic liquid mixtures, l-hexyl-3- methylimidazolium bromide (HMIMBr) + l-hexyl-3-methylimidazolium tetrafluoroborate (HMIMBF4), at the air/water surface were investigated by surface tensiometry and the total-reflection XAFS (TRXAFS) method. Tensiometry showed that the surface density Of BF4 - was much larger than that of Br-, the adsorbed films of the HMIMBr-HMIMBF4 mixture were greatly enriched in BF 4- at all surface tensions, and the excess Gibbs energy of adsorption was positive. However, TRXAFS revealed that the Br ions were all in the free-Br state solvated by six water molecules in the mixed adsorbed film. Entropy-originated nonideal mixing, where a kind of segregation of the counterion distribution takes place in the interfacial region, was suggested in the mixture.
| Original language | English |
|---|---|
| Pages (from-to) | 9954-9959 |
| Number of pages | 6 |
| Journal | Langmuir |
| Volume | 25 |
| Issue number | 17 |
| DOIs | |
| Publication status | Published - Sep 1 2009 |
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All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Surfaces and Interfaces
- Spectroscopy
- Electrochemistry
Cite this
Miscibility and distribution of counterions of imidazolium ionic liquid mixtures at the air/water surface. / Shimamoto, Kei; Onohara, Asuka; Takumi, Hiroki; Watanabe, Iwao; Tanida, Hajime; Matsubara, Hiroki; Takiue, Takanori; Aratono, Makoto.
In: Langmuir, Vol. 25, No. 17, 01.09.2009, p. 9954-9959.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Miscibility and distribution of counterions of imidazolium ionic liquid mixtures at the air/water surface
AU - Shimamoto, Kei
AU - Onohara, Asuka
AU - Takumi, Hiroki
AU - Watanabe, Iwao
AU - Tanida, Hajime
AU - Matsubara, Hiroki
AU - Takiue, Takanori
AU - Aratono, Makoto
PY - 2009/9/1
Y1 - 2009/9/1
N2 - The miscibility and distribution of Br- and BF4 - ions of imidazolium ionic liquid mixtures, l-hexyl-3- methylimidazolium bromide (HMIMBr) + l-hexyl-3-methylimidazolium tetrafluoroborate (HMIMBF4), at the air/water surface were investigated by surface tensiometry and the total-reflection XAFS (TRXAFS) method. Tensiometry showed that the surface density Of BF4 - was much larger than that of Br-, the adsorbed films of the HMIMBr-HMIMBF4 mixture were greatly enriched in BF 4- at all surface tensions, and the excess Gibbs energy of adsorption was positive. However, TRXAFS revealed that the Br ions were all in the free-Br state solvated by six water molecules in the mixed adsorbed film. Entropy-originated nonideal mixing, where a kind of segregation of the counterion distribution takes place in the interfacial region, was suggested in the mixture.
AB - The miscibility and distribution of Br- and BF4 - ions of imidazolium ionic liquid mixtures, l-hexyl-3- methylimidazolium bromide (HMIMBr) + l-hexyl-3-methylimidazolium tetrafluoroborate (HMIMBF4), at the air/water surface were investigated by surface tensiometry and the total-reflection XAFS (TRXAFS) method. Tensiometry showed that the surface density Of BF4 - was much larger than that of Br-, the adsorbed films of the HMIMBr-HMIMBF4 mixture were greatly enriched in BF 4- at all surface tensions, and the excess Gibbs energy of adsorption was positive. However, TRXAFS revealed that the Br ions were all in the free-Br state solvated by six water molecules in the mixed adsorbed film. Entropy-originated nonideal mixing, where a kind of segregation of the counterion distribution takes place in the interfacial region, was suggested in the mixture.
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U2 - 10.1021/la901114e
DO - 10.1021/la901114e
M3 - Article
VL - 25
SP - 9954
EP - 9959
JO - Langmuir
JF - Langmuir
SN - 0743-7463
IS - 17
ER -