Query: PMMA Ionic Liquid gels

title: Highly Conductive Ionic Liquid Gels Prepared with Orthogonal Double Networks of a Low Molecular Weight Gelator and Cross Linked Polymer.
abstract: We prepared a heterogeneous double network (DN) ionogel containing a low molecular weight gelator network and a polymer network that can exhibit high ionic conductivity and high mechanical strength. An imidazolium based ionic liquid was first gelated by the molecular self assembly of a low molecular weight gelator (benzenetricarboxamide derivative) and methyl methacrylate was polymerized with a cross linker to form a cross linked poly(methyl methacrylate) (PMMA) network within the ionogel. Microscopic observation and calorimetric measurement revealed that the fibrous network of the low molecular weight gelator was maintained in the DN ionogel. The PMMA network strengthened the ionogel of the low molecular weight gelator and allowed us to handle the ionogel using tweezers. The orthogonal DNs produced ionogels with a broad range of storage elastic moduli. DN ionogels with low PMMA concentrations exhibited high ionic conductivity that was comparable to that of a neat ionic liquid. The present study demonstrates that the ionic conductivities of the DN and single network, low molecular weight gelator or polymer ionogels strongly depended on their storage elastic moduli.

title: Chloride Ion Conducting Polymer Electrolytes Based on Cross linked PMMA PP14Cl PP14TFSI Ion Gels for Chloride Ion Batteries
abstract: Chloride ion conducting polymer electrolytes based on cross linked ion gels for chloride ion batteries were prepared by in situ photo induced copolymerization of methyl methacrylate (MMA) and ethylene glycol dimethacrylate cross linker (EGDMA) in the presence of ionic liquid mixture, 0.5 M 1 butyl 1methylpiperidinium chloride (PP14Cl) in 1 butyl 1 methylpiperidinium bis(trifluoromethylsulfonyl)imide (PP14TFSI) The as prepared ion gel membranes with 80 wt% chloride containing ionic liquid mixture are self standing, flexible and transparent with superior thermal (up to about 340 oC) and electrochemical stability (5.0 V vs. SS/SS) The ionic conductivity of chloride ion conducting IL based gel polymer electrolytes (IL GPEs) reached 0.9x10 S cm with 80 wt% ionic liquid mixture at 25 oC. Preliminary charge and discharge testing has demonstrated the feasibility of using chloride ion conducting IL GPEs for chloride ion batteries.

title: Spontaneous ionic polarization in ammonia based ionic liquid
abstract: Ionic liquids and gels have attracted attention for a variety of energy storage applications, as well as for high performance electrolytes for batteries and supercapacitors. Although the electronic structure of ionic electrolytes in these applications is of practical importance for device design and improved performance, the understanding of the electronic structure of ionic liquids and gels is still at an early stage. Here we report soft X ray spectroscopic measurements of the surface electronic structure of a representative ammonia based ionic gel (DEME TFSI with PS PMMA PS copolymer) We observe that, near the outermost surface, the area of the anion peak (1s N core level in TFSI) is relatively larger than that of the cation peak (N+ in DEME) This spontaneous ionic polarization of the electrolyte surface, which is absent for the pure ionic liquid without copolymer, can be directly tuned by the copolymer content in the ionic gel, and further results in a modulation in work function. These results shed.

title: Ion gels prepared by in situ radical polymerization of vinyl monomers in an ionic liquid and their characterization as polymer electrolytes.
abstract: To realize polymer electrolytes with high ionic conductivity, we exploited the high ionic conductivity of an ionic liquid. In situ free radical polymerization of compatible vinyl monomers in a room temperature ionic liquid, 1 ethyl 3 methyl imidazolium bis(trifluoromethane sulfonyl)imide (EMITFSI) afforded a novel series of polymer electrolytes. Polymer gels obtained by the polymerization of methyl methacrylate (MMA) in EMITFSI in the presence of a small amount of a cross linker gave self standing, flexible, and transparent films. The glass transition temperatures of the gels, which we named "ion gels" decreased with increasing mole fraction of EMITFSI and behaved as a completely compatible binary system of poly(methyl methacrylate) (PMMA) and EMITFSI. The temperature dependence of the ionic conductivity of the ion gels followed the Vogel Tamman Fulcher (VTF) equation, and the ionic conductivity at ambient temperature reached a value close to 10( 2) S cm( 1) Similarly to the behavior of the ionic liquid, the cation in the ion gels diffused faster than the anion. The number of carrier ions, calculated from the Nernst Einstein equation, was found to increase for an ion gel from the corresponding value for the ionic liquid itself. The cation transference number increased with decreasing EMITFSI concentration due to interaction between the PMMA matrix and the TFSI( anion, which prohibited the formation of ion clusters or associates, as was the case for the ionic liquid itself.

title: Improved lithium ion dynamics in crosslinked PMMA gel polymer electrolyte
abstract: Since PMMA based gel polymer electrolytes could substitute PVDF HFP based gels currently used in Li ion batteries at lower financial and environmental costs, we investigate here the solvation and transport properties of the lithium ions in a crosslinked PMMA based gel polymer electrolyte by a combination of thermal and electrochemical methods, Raman spectroscopy, pulse field gradient (PFG) and electrophoretic NMR (eNMR) techniques, as well as ab initio calculations. The conductivity of the gel containing 10 wt% polymer is only reduced by 14% relative to the liquid electrolyte. In addition, the co solvation by polymer functional groups, a priori expected to slow lithium transport relatively to the anion, has instead a positive effect on lithium transport. Indeed, the ester groups not only participate in lithium solvation and increase ionic dissociation, but since this interaction is rather weak, rather than lowering the lithium diffusion relatively to other species, it mainly decorrelates lithium transport from anionic mobility. Compared to its liquid fraction, the gels show, at the same time, better dissociation and a higher lithium transference number, which results in a higher cationic conductivity, despite the overall conductivity loss.

title: Polymer in ionic liquid electrolytes
abstract: In order to achieve high conductivity in a polymer electrolyte, polymer in ionic liquid electrolytes have been explored. It is found in this study that poly [vinylpyrrolidone co (vinyl acetate) (P(VP c VA) in 1 ethyk 3 methylimidazolium bis(trifluoromethyl sulfonyl) amide (EtMeIm Tf2N and poly(N,N dimethyl acrylamide) (PDMAA) in trimethyl butyl ammonium bis(trifluoromethane sulfonyl) amide (N 1114 Tf 2 N produce ion conducting liquids and gels. The P(VP c VA) EtMeIm Tf 2 N mixture has a conductivity around 10 3 S cm 1 at 22degC, for copolymer concentrations up to 30 wt. Thermal analysis shows that the Tg of the PVP(VP c VA) EtMeIm Tf 2 N system is well described by the Fox equation as a function of polymer content. Poly(methyl methacrylate) (PMMA) EtMeIm Tf 2 N gel electrolytes were prepared by in situ polymerisation of the monomer in the ionic liquid. In the presence of 0.5 2.0 wt. of a crosslinking agent, these PMMA based electrolytes displayed elastromeric properties and high conductivity (ca. 10 3 S. cm 1 at room temperature.

title: Stereocomplex Formation of Isotactic and Syndiotactic Poly(methyl methacrylate)s in Ionic Liquids Leading to Thermoreversible Ion Gels
abstract: We found that stereoregular isotactic poly(methyl methacrylate) (it PMMA) (mm 97% and syndiotactic poly(methyl methacrylate) (st PMMA) (rr 90% with a narrow molecular weight distribution form a stereocomplex in ionic liquids such as 1 butyl 3 methylimidazolium hexafluorophosphate (BMIPF6) The stereocomplex formation brought about the gelation of BMIPF6 and was fully thermoreversible accompanied by a sol gel transition at around the melting point of the crystalline stereocomplex in BMIPF6 as evidenced by differential scanning calorimetry and polarized optical microscopy measurements of the gel. The effects of ionic liquids, the molar ratio of the it and st PMMAs, and the heating and cooling rates on the stereocomplex formation accompanied by gelation were also investigated. The fully thermoreversible gel in the ionic liquid with a high melting point (Tm 175.0 degC) due to the unique stereocomplex formation may provide a new opportunity to fabricate advanced electrochemical devices.

title: The role of the solvent in PMMA gel polymer electrolytes
abstract: Ionic mobility and solvent vapor pressure were studied on gels containing sodium perchlorate, polymethylmethacrylate and sulfolane as a solvent. The excess of solvent increases markedly the mobility of ions and is indicated by solvent evaporation at elevated temperature. The solvent is bonded similarly as in the liquid solution of sodium salt. The heat of solvent evaporation from gels is near to that of pure solvents.

title: Heat capacities and glass transitions of ion gels.
abstract: We have investigated thermodynamic properties of ion gels consisting of a PMMA [poly(methyl methacrylate) network and EMITFSI [1 ethyl 3 methylimidazolium bis(trifluoromethanesulfonyl)imide] ionic liquid by means of an adiabatic calorimeter. The heat capacity data were measured in the temperature range between 5 and 375 K for 7 samples with x 0 (pure PMMA) 0.10, 0.18, 0.27, 0.48, 0.65, and 1.0 (pure ionic liquid) where x is a mole fraction of EMITFSI. These data revealed that two broad but distinct glass transitions appeared in the low x region. The upper glass transition is mainly due to the freezing of the PMMA motion, while the lower one is due to the ionic liquid. The upper glass transition temperature T(g) drastically decreased with increasing x, reflecting a large plasticization effect observed in mechanical experiments. The x dependence of the T(g)s and the excess heat capacities gave new physical insight to the interaction between polymer and ionic liquid in ion gels.

title: Mechanically robust and thermally stable electrochemical devices based on star shaped random copolymer gel electrolytes
abstract: We synthesized 6 arm star shaped polystyrene ran poly(methyl methacrylate) copolymers (S r M)6) for mechanically robust and thermally stable ion gels containing an ionic liquid of 1 ethyl 3 methylimidazolium bis(trifluoromethyl sulfonyl)imide [EMI][TFSI] The (S r M)6 based gels exhibited higher elastic modulus (E 1.67 x 105 Pa) which is more than five times that ~0.29 x 105 Pa) of linear PS r PMMA based ion gels at the same Sty content ~29 mol% irrespective of applied mechanical strains (stretching and compression) In addition, they showed outstanding thermal stability. For example, the gel sol transition temperature (Tgel) of (S r M)6 gels was ~72 degC, compared with that ~56 degC) of linear PS r PMMA based ion gels. These physical properties of gels were further improved by increasing total molecular weight and the fraction of styrene, giving E of ~3.8 x 105 Pa and Tgel of ~163 degC. The resulting gels were functionalized by introducing electrochemiluminescence luminophores (tris(2,2' bipyridyl)ruthenium(II) hexafluorophosphate) By utilizing the mechanical robustness of the (S r M)6 gels, we fabricated emissive electrochemical displays through 'cut and stick' process. Moreover, the thermally stable (S r M)6 gels indicated good dimensional stability, offering a chance to demonstrate ECL devices that operate even at high temperatures.