Ion Gels by Self-Assembly of a Triblock Copolymer in an Ionic Liquid

He, Yiyong; Boswell, Paul G.; Bühlmann, Philippe; Lodge, Timothy P.

doi:10.1021/jp064574n

Cited by 301 publications

(377 citation statements)

References 65 publications

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“…142 As mentioned above, block copolymer melts, the solids or theirs concentrated solutions, are macroscopically homogeneous but possess predictable structural heterogeneity at length scales of a few nanometers up to several micrometers. 143,144 Such nanostructures have well-known ordered states (cubic, lamellar, hexagonal, and bicontinuous phases).…”

Section: Self-assembly Of Block Copolymers In Ionic Liquidsmentioning

confidence: 99%

Polymers in Ionic Liquids: Dawn of Neoteric Solvents and Innovative Materials

Ueki

Watanabe

2011

Bulletin of the Chemical Society of Japan

155

144

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In this paper, we review recent advances in the use of polymers in ionic liquids (ILs) from the view point of the "dawn of neoteric solvents and innovative materials." The first part of this paper presents a brief review of the solubility parameters of ILs, which are expected to serve as a qualitative guide for predicting polymer solubility in ILs; however, this concept cannot be used to rationalize a number of cases in which strong Coulombic interactions dominate the solubility parameters of the ILs. Thus, solubility of 24 different common synthetic polymers is experimentally demonstrated under dilute conditions (3 wt %) in four different common ILs. It is found that the Lewis basicities of the counter anions in the ILs play an important role in determining the solubility of the polymers. ILs can also be used as good solvents for low-solubility biopolymers and as good dispersion media of carbon nanotubes, which contributes to the fields of biorefinery processes and advanced materials. Certain combinations of polymers in ILs undergo phase separations as the temperature of the solutions is varied. The solubility of a nonionic polymer in water generally decreases with increasing temperature, and certain combinations exhibit lower critical solution temperature (LCST) phase separation, whereas the solubility of a polymer in an organic solvent generally increases with increasing temperature and in some cases upper critical solution temperature (UCST) phase separation is observed. Interestingly, both LCST and UCST phase separations are observed for certain polymers in ILs. After presenting possible explanations of the solubility of polymers in ILs, recent developments in the field of thermosensitive polymers in ILs are discussed from the perspective of materials science, where such phase separations are exploited to trigger abrupt changes in polymer properties. The final part of this review describes the thermosensitive self-assembly of block copolymers in ILs. Similar to conventional molecular solvents, block copolymers in ILs exhibit variable self-assemblies in solution and in the bulk.

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Section: Self-assembly Of Block Copolymers In Ionic Liquidsmentioning

confidence: 99%

Polymers in Ionic Liquids: Dawn of Neoteric Solvents and Innovative Materials

Ueki

Watanabe

2011

Bulletin of the Chemical Society of Japan

155

144

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“…51,52 Block copolymers containing PEO segments and IL-incompatible segments, which form micelles in ILs, have been studied and successfully utilized for micellar shuttles at the IL/water interfaces and in thermoreversible ion-gel formation. [53][54][55][56][57][58] As shown in Table 3, polyethers other than PEO, such as PGME, PEEGE, PEGE and PPO, exhibit LCST phase separation in these ILs. This result is very important, because PPO and its block copolymers are commercially available and we can systematically examine these LCST behaviors.…”

Section: Influence Of Polymer Structures On Phase Separation Temperatmentioning

confidence: 99%

Structural effects of polyethers and ionic liquids in their binary mixtures on lower critical solution temperature liquid-liquid phase separation

Kodama

Tsuda

Niitsuma

et al. 2011

Polym J

103

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The solubility and phase behavior of five polyethers (poly(ethylene oxide), poly(glycidyl methyl ether), poly(ethyl glycidyl ether), poly(ethoxyethyl glycidyl ether) and poly(propylene oxide)) in 14 different room-temperature ionic liquids (ILs) were studied by changing the structures of polyethers and the cations and anions in the ILs. Certain combinations of a polyether and an IL binary mixture exhibited lower critical solution temperature (LCST) phase behavior. For ILs containing the same anions, the polyethers were highly soluble in imidazolium-or pyridinium-based ILs, whereas they were insoluble in ammonium-or phosphonium-based ILs. An increase in length of the alkyl chain in the imidazolium cation and an increase in polarity of the polyethers resulted in a higher LCST phase separation temperature, whereas substitution of the hydrogen atoms on the imidazolium ring by methyl groups resulted in a lower LCST phase separation temperature. The hydrogen bonding interaction between the oxygen atoms in the polyethers and the aromatic hydrogen atoms on the cations in the ILs had an important role in the LCST phase behavior of the mixtures. Miscibility of the mixtures was also affected by the Lewis basicity of the anions in the ILs.

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“…a polyelectrolyte [58] or a block copolymer [59] . Ion gels exhibit easy handling film forming properties of the solid-state combined with the high ionic conductivity of ionic liquids (in the range of 10 -4 -10 -2 S cm -1 ) [60] .…”

Section: Ionic Gelsmentioning

confidence: 99%

Polyelectrolyte‐Gated Organic Field Effect Transistors – Printing and Electrical Stability

Sinno¹

2013

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The progress in materials science during recent decades along with the steadily growing desire to accomplish novel functionalities in electronic devices and the continuous strive to achieve a more efficient manufacturing process such as low-cost robust high-volume printing techniques, has brought the organic electronics field to light. For example, organic field effect transistors (OFETs) are the fundamental building blocks of flexible electronics. OFETs present several potential advantages, such as solution processability of organic materials enabling their deposition by various printing methods at low processing temperatures, the possibility to coat large areas, and the mechanical flexibility of polymers that is compatible with plastic substrates. Employing polyelectrolytes as gate insulators in OFETs allows low-voltage operation in the range of 1 V, suppresses unintended electrochemical doping of the semiconductor bulk, and provides tolerance to thicker gate insulator layers and to the gate electrode alignment over the channel which eases the design and manufacturing requirements. These features place polyelectrolyte-gated OFETs (EGOFETs) as promising candidates to be realized in low-cost, large-area, light-weight, flexible electronic applications.The work in this thesis focuses on EGOFETs and their manufacturing using the inkjet printing technology. EGOFETs have been previously demonstrated using conventional manufacturing techniques. Several challenges have to be overcome when attempting to achieve a fully printed EGOFET, with the incompatible wetting characteristics of the semiconductor/polyelectrolyte interface being one of the main problems. This issue is addressed in paper I and paper II. Paper I presents a surface modification treatment where an amphiphilic diblock copolymer is deposited on the surface to enable the printability of the semiconductor on top of the polyelectrolyte. Paper II introduces an amphiphilic semiconducting copolymer that can switch its surface from hydrophobic to hydrophilic, when spread as thin film, upon exposure to water. Moreover, characterization of the reliability and stability of EGOFETs in terms of bias stress is reported. Bias stress is an undesired operational instability, usually manifested as a decay in the drain current, triggered by the gradual shift of the threshold voltage of the transistor under prolonged operation. This effect has been extensively studied in different OFET structures, but a proper understanding of how it is manifested in EGOFETs is still lacking. Bias stress depends strongly on the material, how it is processed, and on the transistor operating conditions. Papers III and IV report bias stress effects in EGOFET devices and inverters, respectively. The proposed mechanism involves an electron transfer reaction between adsorbed water and the charged semiconductor channel, which promotes the generation of extra protons that subsequently diffuse into the polyelectrolyte. Understanding and controlling the mechanism of bias stress in EGOFETs is c...

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Ion Gels by Self-Assembly of a Triblock Copolymer in an Ionic Liquid

Cited by 301 publications

References 65 publications

Polymers in Ionic Liquids: Dawn of Neoteric Solvents and Innovative Materials

Polymers in Ionic Liquids: Dawn of Neoteric Solvents and Innovative Materials

Structural effects of polyethers and ionic liquids in their binary mixtures on lower critical solution temperature liquid-liquid phase separation

Polyelectrolyte‐Gated Organic Field Effect Transistors – Printing and Electrical Stability

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