Specialist Gelator for Ionic Liquids

Abstract

Cyclo(l-beta-3,7-dimethyloctylasparaginyl-L-phenylalanyl) (1) and cyclo(L-beta-2-ethylhexylasparaginyl-L-phenylalanyl) (2), prepared from L-asparaginyl-L-phenylalanine methyl ester, have been found to be specialist gelators for ionic liquids. They can gel a wide variety of ionic liquids, including imizazolium, pyridinium, pyrazolidinium, piperidinium, morpholinium, and ammonium salts. The mean minimum gel concentrations (MGCs) necessary to make gels at 25 degrees C were determined for ionic liquids. The gel strength increased at a rate nearly proportional to the concentration of added gelator. The strength of the transparent gel of 1-butylpyridinium tetrafluoroborate ([C(4)py]BF(4)), prepared at a concentration of 60 g L(-1) (gelator 1/[C(4)py]BF(4)), was ca. 1500 g cm(-2). FT-IR spectroscopy indicated that a driving force for gelation was intermolecular hydrogen bonding between amides and that the phase transition from gel to liquid upon heating was brought about by the collapse of hydrogen bonding. The gels formed from ionic liquids were very thermally stable; no melting occurs up to 140 degrees C when the gels were prepared at a concentration of 70 g L(-1) (gelator/ionic liquid). The ionic conductivities of the gels were nearly the same as those of pure ionic liquids. The gelator had electrochemical stability and a wide electrochemical window. When the gels were prepared from ionic liquids containing propylene carbonate, the ionic conductivities of the resulting gels increased to levels rather higher than those of pure ionic liquids. The gelators also gelled ionic liquids containing supporting electrolytes.

Self-recovering stimuli-responsive macrocycle-equipped supramolecular ionogels with unusual mechanical properties

“…13 The LMWG-based ionogels reported so far have great potential in that they combine the advantages of ionic liquids with the particular mechanical properties of supramolecular gels. 14 However, the stimuli responsiveness of the most known ionogels has so far been restricted to thermally reversible 15 and photo-responsive ionogels. 16 Also, the mechanical strengths of LMWG-based ionogels are usually far from that required for practical uses.…”

Physical Gelation by Low-Molecular-Weight Compounds and Development of Gelators

“…Compound 9 can gel alcohols, esters, ketones, aromatic compounds, soy oil, glycerides and decamethylcyclopentasiloxane, as well as various ionic liquids. 31 The wide range of compounds gelled with 9 suggests that 9 can be used as a lead compound for designing new gelators containing functional groups. For example, designed compounds 10 32 13 are based on 9 and exhibit gelation ability.…”

Analysis of Bacterial Cellulose/Ionic Liquid MWCNTs via Cyclic Voltammetry

“…Also ILs polymers of polymerizable ionic liquid monomers have been constructed as exotic polyelectrolytes. ILs are tended to use as plasticizers of polymers in some categorize and as key components in novel classes of polymer gels [17]- [19]. Although an Ionic liquid's characteristic is an excellent ionic conductivity, depends on its decomposition temperature.…”

“…Hence it is advantageous to convert IL-based electrolyte solutions into a solid or quasi-solid form. Recently, ILs-Gelation has been the most studied issues and supported both physical and chemical gelations [18] [19]. Among these methods have been used for the gelation of ILs, inorganic nanoparticles, Low-molecular weight compounds, single-walled carbon nanotubes are successful [22].…”