Rheopectic Gel Formation of Stimuli-Responsive Ionic Liquid/Water Mixtures

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.

2016 ◽  
Vol 52 (51) ◽  
pp. 7970-7973 ◽  
Author(s):  
Shengyi Dong ◽  
Jan Heyda ◽  
Jiayin Yuan ◽  
Christoph A. Schalley

Unique LCST phase behaviour of imidazolium-based ionic liquids is reported, which can be controlled by concentration, the choice of cation, anion and solvent, and by supramolecular complex formation. MD simulations provide insight into the molecular basis of this LCST phenomenon.


Author(s):  
Terence Yan King Ho ◽  
Ankit . ◽  
Benny Febriansyah ◽  
Natalia Yantara ◽  
Shreyas Pethe ◽  
...  

Hydrogels are able to exhibit optical transitions in the presence of external stimuli such as temperature, driven by the lower critical solution temperature (LCST) phenomena. However, they suffer from inherent...


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.


2016 ◽  
Vol 52 (47) ◽  
pp. 7497-7500 ◽  
Author(s):  
Yuki Kohno ◽  
Douglas L. Gin ◽  
Richard D. Noble ◽  
Hiroyuki Ohno

A new type of poly(ionic liquid) membrane, which shows switchable hydrated states via lower critical solution temperature-type phase behaviour, enables concentration of some water-soluble proteins from aqueous media.


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.


Author(s):  
Gore S. A. ◽  
Gholve S. B. ◽  
Savalsure S. M. ◽  
Ghodake K. B. ◽  
Bhusnure O. G. ◽  
...  

Smart polymers are materials that respond to small external stimuli. These are also referred as stimuli responsive materials or intelligent materials. Smart polymers that can exhibit stimuli-sensitive properties are becoming important in many commercial applications. These polymers can change shape, strength and pore size based on external factors such as temperature, pH and stress. The stimuli include salt, UV irradiation, temperature, pH, magnetic or electric field, ionic factors etc. Smart polymers are very promising applicants in drug delivery, tissue engineering, cell culture, gene carriers, textile engineering, oil recovery, radioactive wastage and protein purification. The study is focused on the entire features of smart polymers and their most recent and relevant applications. Water soluble polymers with tunable lower critical solution temperature (LCST) are of increasing interest for biological applications such as cell patterning, smart drug release, DNA sequencing etc.


Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 329
Author(s):  
Seidai Okada ◽  
Eriko Sato

Coumarin-containing vinyl homopolymers, such as poly(7-methacryloyloxycoumarin) (P1a) and poly(7-(2′-methacryloyloxyethoxy)coumarin) (P1b), show a lower critical solution temperature (LCST) in chloroform, which can be controlled by the [2 + 2] photochemical cycloaddition of the coumarin moiety, and they are recognized as monofunctional dual-stimuli-responsive polymers. A single functional group of monofunctional dual-stimuli-responsive polymers responds to dual stimuli and can be introduced more uniformly and densely than those of dual-functional dual-stimuli-responsive polymers. In this study, considering a wide range of applications, organogels consisting of P1a and P1b, i.e., P1a-gel and P1b-gel, respectively, were synthesized, and their thermo- and photoresponsive behaviors in chloroform were investigated in detail. P1a-gel and P1b-gel in a swollen state (transparent) exhibited phase separation (turbid) through a temperature jump and reached a shrunken state (transparent), i.e., an equilibrium state, over time. Moreover, the equilibrium degree of swelling decreased non-linearly with increasing temperature. Furthermore, different thermoresponsive sites were photopatterned on the organogel through the photodimerization of the coumarin unit. The organogels consisting of homopolymers of coumarin-containing methacrylate exhibited unique thermo- and photoresponsivities and behaved as monofunctional dual-stimuli-responsive organogels.


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