@article {2460,
	title = {Hydrophobicity/Hydrophilicity of 1-Butyl-2,3-dimethyl and 1-Ethyl-3-methylimodazolium Ions: Toward Characterization of Room Temperature Ionic Liquids},
	journal = {Journal of Physical Chemistry B},
	volume = {113},
	number = {44},
	year = {2009},
	note = {ISI Document Delivery No.: 510QMTimes Cited: 2Cited Reference Count: 52Kato, Hitoshi Miki, Kumiko Mukai, Tomohiro Nishikawa, Keiko Koga, Yoshikata},
	month = {Nov},
	pages = {14754-14760},
	type = {Article},
	abstract = {We continue to experimentally characterize the constituent ions of room temperature ionic liquids in terms of their interactions with H2O. By using the so-called 1-propanol probing methodology, we experimentally index the relative hydrophobicity/hydrophilicity of a test ion. In this paper, we examine 1-butyl-2,3 dimethylimidazolium (abbreviated as [C(4)C(1)mim](+)) and 1-ethyl-3-methylimidazolium ([C(2)mim](+)). We found that [C(4)C(1)mim](+) dissociates completely in dilute aqueous solution less than 0.006 mol fraction, and hence, its hydrophobicity/hydrophilicity could be determined. The results indicate that [C(4)C(1)mim](+) is highly amphiphilic with much stronger hydrophobicity and hydrophilicity than normal ions. Our earlier similar studies indicated the same conclusion for such typical constituent ions as 1-butyl-3-methylimidazolium ([C(4)mim](+)) PF6-, CF3SO3-, and N(SO2CF3)(2)(-). Hence, we suggest that the constituent ions of room temperature ionic liquids that we have studied so far are all amphiphiles with much stronger hydrophobicity and hydrophilicity than normal ions. We found, furthermore, that the hydrophobicity and hydrophilicity of [C(4)C(1)mim](+) are stronger than those for [C(4)mim](+). A possible reason for higher hydrpohilicity is discussed in terms of strong acidic character of H on the C(2) of the imidazolium ring, which tends to attract the delocalized positive charge toward itself oil forming a hydrogen bond to H2O. On replacing it with CH3 in [C(4)C(1)mim](+), the lack of acidic H enhances the positive charge in the vicinity of N-C-N in the ring that interacts with the surrounding H2O strongly to an induced dipole of O of the H2O. For [C(2)mim](+), we found it does not dissociate completely, even in dilute aqueous solution, and hence, we could not characterize it within the present methodology.},
	keywords = {1-BUTYL-3-METHYLIMIDAZOLIUM BROMIDE, AGGREGATION BEHAVIOR, ALKYL CHAIN-LENGTH, APPROACH, AQUEOUS-SOLUTIONS, HOFMEISTER SERIES, MIXING SCHEMES, MOLECULAR-ORGANIZATION, partial molar enthalpy, PHYSICOCHEMICAL PROPERTIES, THERMODYNAMIC},
	isbn = {1520-6106},
	url = {<Go to ISI>://000271105600027},
	author = {Kato, H. and Miki, K. and Mukai, T. and Nishikawa, K. and Koga,Yoshikata}
}
@article {2123,
	title = {Chemical Potentials in Aqueous Solutions of Some Ionic Liquids with the 1-Ethyl-3-methylimidazolium Cation},
	journal = {Journal of Physical Chemistry B},
	volume = {112},
	number = {42},
	year = {2008},
	note = {ISI Document Delivery No.: 361AWTimes Cited: 3Cited Reference Count: 33Kato, Hitoshi Nishikawa, Keiko Murai, Hiromi Morita, Takeshi Koga, Yoshikata},
	month = {Oct},
	pages = {13344-13348},
	type = {Article},
	abstract = {We determined the vapor pressures of aqueous solutions of 1-ethyl-3-methylimidazolium ([C(2)mim])-based ionic liquids (IL) with counteranions, tetrafluoroborate (BF4-), trifluoromethanesulfonate (OTF-), and iodide (I-) Because in literature the evidence is accumulating and pointing to the fact that ionic liquid ions do not dissociate in aqueous media for the most of the concentration range, we analyzed the vapor pressure data on the basis of binary mixture, and the excess chemical potentials of each component were calculated. From these, the intermolecular interactions in terms of excess chemical potential and hence the concentration fluctuations were evaluated. Though any further discussion into the mixing schemes of the mixture awaits the excess partial molar enthalpy and hence the excess partial molar entropy data, the net interaction in terms of excess chemical potential indicates that the affinity of each IL is ranked in the descending order [C2mim]l > [C(2)mim]OTF > [C(2)mim]BF4. This is consistent with our earlier findings that [C(2)mim](+) is modestly amphiphilic with almost equal hydrophobicity and hydrophilicity, I- is a hydrophile, and OTF- is amphiphilic, and BF4- is believed to be strongly hydrophobic.},
	keywords = {1-BUTYL-3-METHYLIMIDAZOLIUM, ACETONITRILE, AGGREGATION BEHAVIOR, ENTHALPY-ENTROPY COMPENSATION, MIXING SCHEMES, MOLECULAR-ORGANIZATION, SYSTEMS, TETRAFLUOROBORATE, TETRAFLUOROBORATE PLUS WATER, THERMODYNAMIC APPROACH, VAPOR-PRESSURE MEASUREMENT},
	isbn = {1520-6106},
	url = {<Go to ISI>://000260100900026},
	author = {Kato, H. and Nishikawa, K. and Murai, H. and Morita, T. and Koga,Yoshikata}
}
@article {2226,
	title = {Synthesis of thermoresponsive mixed arm star polymers by combination of RAFT and ATRP from a multifunctional core and its self-assembly in water},
	journal = {Macromolecules},
	volume = {41},
	number = {12},
	year = {2008},
	note = {ISI Document Delivery No.: 314XSTimes Cited: 22Cited Reference Count: 80Ranganathan, Krishnan Deng, Rui Kainthan, Rajesh K. Wu, Chi Brooks, Donald E. Kizhakkedathu, Jayachandran N.},
	month = {Jun},
	pages = {4226-4234},
	type = {Article},
	abstract = {Mixed arm star copolymers of poly(N,N-dimethylacrylamide) (PDMA) and poly(N-isopropylacrylamide) (PNIPAm) were synthesized by a sequential reversible addition - fragmentation chain transfer (RAFT) and atom transfer radical polymerization (ATRP) from a multi-initiator-functionalized hyperbranched polyglycerol (MI-HPG) core. The MI-HPG core was synthesized from an amine-functionalized polyglycerol, modified successively with 2-chloropropionamide groups (ATRP initiator) and 4,4{\textquoteright}-azobis(4-cyanovaleric acid) (azo initiator). N,N-Dimethylacrylamide was polymerized from MI-HPG core by the RAFT method using S,S{\textquoteright}-bis(alpha,alpha{\textquoteright}-dimethyla-alpha {\textquoteright}{\textquoteright}-acetic acid)trithiocarbonate as a chain transfer agent (CTA) in acetic acid/sodium acetate aqueous buffer solutions. The ratio of [CTA]/[azo initiator] was critical in controlling the molecular weight of the PDMA grafts from MI-HPG core (HPG-g-PDMA). Controlled synthesis of mixed arm star copolymers was achieved by cografting PNIPAm on to the HPG-g-PDMA macroinitiator by ATRP. The temperature-induced phase transition of aqueous solutions of hybrid HPG-g-PDMA/PNIPAm star copolymers was studied by H-1 NMR, UV-vis spectroscopy, and laser light scattering. Results show that the mixed arm star copolymers exist as either single molecules or small aggregates below the phase transition temperature (LCST) of PNIPAm in aqueous solutions. All the star copolymers formed intermolecular aggregates above the LCST of PNIPAm possibly due to the hydrophobic interaction between collapsed PNIPAM chains. These aggregates have micelle-like structure with PNIPAm core and PDMA corona. The formation of intermolecular aggregates and the stabilization of aggregates depend on the molecular weight of arms and composition of the star copolymer.},
	keywords = {AGGREGATION BEHAVIOR, AQUEOUS-SOLUTION PROPERTIES, DIBLOCK COPOLYMERS, FRAGMENTATION CHAIN TRANSFER, HYDROPHILIC BLOCK-COPOLYMERS, HYPERBRANCHED POLYGLYCEROL CORE, POLY(ETHYLENE OXIDE), TERTIARY AMINE METHACRYLATES, TO-GLOBULE TRANSITION, TRANSFER RADICAL POLYMERIZATION},
	isbn = {0024-9297},
	url = {<Go to ISI>://000256843100025},
	author = {Ranganathan, K. and Deng, R. and Kainthan, R. K. and Wu, C. and Brooks, D. E. and Kizhakkedathu, J. N.}
}
