Solvent‐Reversible Poration in Ionic Liquid Copolymers

Abstract

An open and closed case: Polymerization of microemulsions stabilized by surfactants based on ionic liquids leads to cross‐linked polymer gels which can be transformed into porous polymers by anion exchange of the ionic liquid moiety. These porous polymers can be converted back into polymer gels by immersion in organic solvents. Subsequent immersion of these gels in water then affords the porous polymers once more (see scheme).

Photonic Ionic Liquids Polymer for Naked‐Eye Detection of Anions

“…[8] For example, Texter and coworkers have synthesized an imidazoliumbased IL copolymer, which can be reversibly tuned between a hydrogel and a porous structure by exchanging counteranions, [9] due to the substantial volume change of ILs induced by its hydrophilicity or hydrophobicity change. It is conceivable that, if two unique properties of ILs and photonic crystal are combined, a novel anionic signaling strategy for ''naked-eye'' anions detection could be developed based on the counteranion exchanging to turn the stop band of photonic crystals.…”

“…The interconnected, highly ordered porous structure cannot only directly generate optical signals due to Bragg diffraction, but also be favorable for the rapid counteranion exchanging within IL films. Since different anion of imidazolium moiety greatly affects the hydrophilicity or hydrophobicity of IL units, [6,7] when a photonic IL film is soaked in an anion aqueous solution, counteranion exchanging will induce its volume change [9] and as a consequence, cause well-defined shift of the stop band of the photonic IL film depending on the type of counteranion. As shown in Figure 2C, the prepared photonic IL film selectively exhibits different stop band shifts upon soaking in diversified aqueous anion solutions.…”

Ionic Liquids and Polymeric Ionic Liquids as Stimuli-Responsive Functional Materials

“…These new materials include elastic conducting thin films, open cell porating monoliths [15,16] and thin films, and stimuli-responsive block copolymers, including a new class of thermoreversible (LCST) gelating lyotropic liquid-crystalline mesophases [43].…”

“…An early review of ionic liquids in microemulsions [28] included cases wherein IL was substituted for an oil in water/IL/surfactant microemulsions [44][45][46], IL was substituted for water in IL/oil/surfactant microemulsions [47][48][49], and IL was substituted for surfactant in water/oil/IL microemulsions [15,16,50,51].…”

“…When such ILs are used to compose new polymers, the resulting polymers will often also exhibit similarly responsive phenomena as well as new phenomena that do not emanate from the respective monomers, but only from their association structures or polymerized structures. The solvent and anion exchange stimuli responsiveness of PIL was recognized in the early work of Mecerreyes and co-workers [14] and of Yan and Texter [15,16], wherein both the tendency for a particular anion to solvophilically or to solvophobically ion pair with an imidazolium counter ion [10] and the tendency for a particular anionimidazolium ion pair to be solvated or not in a particular solvent [16] were observed to generate interesting stimuli responses, such as phase transfer following anion exchange and reversible gel-open cell porous material transitions by so-called spinodal decomposition. Many of these PILs and their applications have been reviewed [17][18][19][20][21][22][23][24][25].…”