Material design of ionic liquids to show temperature-sensitive LCST-type phase transition after mixing with water

2011 ◽  
Vol 64 (12) ◽  
pp. 1560 ◽  
Author(s):  
Yuki Kohno ◽  
Hiroki Arai ◽  
Shohei Saita ◽  
Hiroyuki Ohno

Phosphonium cations bearing different alkyl chains were coupled with several common anions so as to prepare ionic liquids (ILs) with diverse hydrophobicity. A temperature-driven phase behaviour of the mixture of various ILs and water has been examined. A few ILs were found to exhibit temperature-sensitive lower critical solution temperature (LCST)-type phase transition after mixing with water. The phase separation temperature (Tc) of the IL/water mixtures depended strongly on the hydrophobicity of the component ions as well as mixing ratio. The number of water molecules per ion pair in the IL phase (mwater) increased dramatically upon cooling. The temperature dependence of this parameter was found to be useful to predict the possibility of the ILs to show the LCST-type phase behaviour after mixing with water. Since the value of mwater depended on the ion structure, especially on the hydrophobicity, the Tc was accurately set out by suitably mixing two ILs with different hydrophobicity.

2012 ◽  
Vol 65 (1) ◽  
pp. 91 ◽  
Author(s):  
Yuki Kohno ◽  
Hiroyuki Ohno

Tetrabutylphosphonium styrenesulfonate and its homopolymer showed a lower critical solution temperature-type phase transition in water. As the hydrophobicity of these monomeric and polymeric salts affects phase behaviour, the phase transition temperature of the polyelectrolyte was changed by the introduction of monomers having different alkyl chain length on the phosphonium cations.


RSC Advances ◽  
2016 ◽  
Vol 6 (62) ◽  
pp. 57117-57121 ◽  
Author(s):  
Konrad Grygiel ◽  
Weiyi Zhang ◽  
Christophe Detrembleur ◽  
Jiayin Yuan

A poly(vinyl thiazolium) polymer in acetone solution exhibited an unexpected lower critical solution temperature (LCST)-type phase transition.


2013 ◽  
Vol 66 (11) ◽  
pp. 1393 ◽  
Author(s):  
Yuki Kohno ◽  
Yuki Deguchi ◽  
Naomi Inoue ◽  
Hiroyuki Ohno

Polycationic-type homopolymers derived from polymerisable ionic liquids with adequate hydrophobicity were prepared to form spherical nanoparticles in water that changed their diameter as a function of temperature. The diameter change was attributed to a temperature-sensitive and reversible lower critical solution temperature-type phase change of the polymers in water.


2019 ◽  
Vol 10 (2) ◽  
pp. 260-266 ◽  
Author(s):  
Jin-Jin Li ◽  
Yin-Ning Zhou ◽  
Zheng-Hong Luo ◽  
Shiping Zhu

A polyelectrolyte-containing copolymer with a CO2/N2-switchable cloud point, resulting from the gas-induced alternation of hydrophilicity, was prepared.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yen-Ho Chu ◽  
Mou-Fu Cheng ◽  
Yung-Hsin Chiang

Abstract Both lower and upper critical solution temperature (LCST and UCST) systems are two typical phase behaviors of thermoresponsive materials with solvents, in which LCST is far less common than UCST. Recent studies on ionic liquids carrying LCST phase transitions have predominantly focused on quaternary ammonium- and phosphonium-based ionic salts. Based on the 1,2,3-triazole core structure assemblable by azide-alkyne cycloaddition click reaction, this work reports the combinatorial synthesis of 1,3,4-trialkylated 1,2,3-triazolium ionic liquids in three libraries with a total of 160 ionic liquids and demonstrates, for the first time, their values in temperature-switchable phase transition with water. In this work, the successful discovery of a new thermoresponsive ionic liquid b26, based on the structure-and-phase separation study of b8 and b9, perfectly exemplified the true value of the tunability of ionic liquid fine structures. For all 160 ionic liquids synthesized, 155 are liquid at room temperature and 22 room-temperature ionic liquids were found to exhibit thermoresponsive phase transitions having low Tc values in water. To the best of our knowledge, this comprehensive study is the first report of small-molecule 1,2,3-triazolium ionic liquids that exhibit LCST property in water.


2015 ◽  
Vol 51 (75) ◽  
pp. 14183-14186 ◽  
Author(s):  
Daphne Depuydt ◽  
Liwang Liu ◽  
Christ Glorieux ◽  
Wim Dehaen ◽  
Koen Binnemans

Bis(2-ethylhexyl)phosphate ionic liquids show a temperature-dependent phase behaviour of the LCST-type and can extract transition metal ions very efficiently via homogeneous liquid–liquid extraction.


2017 ◽  
Vol 70 (1) ◽  
pp. 74 ◽  
Author(s):  
Yukinobu Fukaya ◽  
Takuro Nakano ◽  
Hiroyuki Ohno

A new class of hydrophobic and polar ionic liquids was prepared by coupling hydrophobic tetraoctylphosphonium cation and polar phosphonate-derived anions. Mixtures of these ionic liquids and water showed lower critical solution temperature-type phase behaviour. Furthermore, these mixtures displayed thermoreversible, however, non-linear viscosity change despite their large content of water. The abrupt increase in the viscosity was explained by the occurrence of rheopectic gelation of the ionic liquid/water mixtures by external stimuli such as shear stress.


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