Ionic liquids amphiphilic behavior

Ionic liquids (ILs) with their outstanding solvent properties, that is, high conductivity, tunable polarity, zero volatility, and high thermal stability, are of growing interest in different fields of application including as a solvent component in microemulsions [6,7]. Thus, the tunable polar properties are of special interest. Therefore, ILs can be used as polar [8-11] as well as nonpolar solvents [12,13], Moreover, ILs can show amphiphilic behavior [14] and are called IL sirnfactants [15], Their physical properties can be adjusted in a characteristic way by varying the molecular structure of ILs. Since the ILs are sterically mismatched ions, they hinder crystal formation. Different cations, for example, ammonium, phosphonium, sulfonium, imidazolium, pyridinium, or pyrrolidinium, with different anions, for example, chloride, bromide, iodide, fluoroborate, or fluorophosphates, can be selected for a broad range of combinations [6]. 

Greaves TL, Weerawardena A, Krodkiewska I, Drummond CJ (2008) Protic ionic liquids physicochemical properties and behavior as amphiphile self-assembly solvents. J Phys Chem B 112 896-905... 

Hydrophobically modified polybetaines combine the behavior of zwitterions and amphiphilic polymers. Due to the superposition of repulsive hydrophobic and attractive ionic interactions, they favor the formation of self-organized and (micro)phase-separated systems in solution, at interfaces as well as in the bulk phase. Thus, glasses with liquid-crystalline order, lyotropic mesophases, vesicles, monolayers, and micelles are formed. Particular efforts have been dedicated to hydrophobically modified polyphosphobetaines, as they can be considered as polymeric lipids [5,101,225-228]. One can emphasize that much of the research on polymeric phospholipids was not particularly focused on the betaine behavior, but rather on the understanding of the Upid membrane, and on biomimicking. So, often much was learnt about biology and the life sciences, but little on polybetaines as such. 

---