Poly , liquid matrix membranes

Many approaches have been developed for the production of ionic liquid-polymer composite membranes. For example, Doyle et al. [165] prepared RTILs/PFSA composite membranes by swelling the Nafion with ionic liquids. When 1-butyl, 3-methyl imidazolium trifluoromethane sulfonate was used as the ionic liquid, the ionic conductivity ofthe composite membrane exceeded 0.1 S cm at 180 °C. A comparison between the ionic liquid-swollen membrane and the liquid itself indicated substantial proton mobility in these composites. Fuller et al. [166] prepared ionic liquid-polymer gel electrolytes by blending hydrophilic RTILs into a poly(vinylidene fiuoridej-hexafluoropropylene copolymer [PVdF(HFP)] matrix. The gel electrolytes prepared with an ionic liquid PVdF(HFP) mass ratio of 2 1 exhibited ionic conductivities >10 Scm at room temperature, and >10 Scm at 100 °C. When Noda and Watanabe [167] investigated the in situ polymerization of vinyl monomers in the RTILs, they produced suitable vinyl monomers that provided transparent, mechanically strong and highly conductive polymer electrolyte films. As an example, a 2-hydroxyethyl methacrylate network polymer in which BPBF4 was dissolved exhibited an ionic conductivity of 10 S cm at 30 °C. 

The versatility of ISEs was enhanced considerably by the introduction of membranes containing neutral ion carriers (ionophores). The first ISE of this type, with a membrane containing valinomycin and selective for potassium ions, was described by Stefanac and Simon in 1966. There are many liquid chemical systems that interact highly selectively with ions through, e.g., ion exchange, ion association, or solvent extraction. Practically useful ISEs based on these systems and on neutral ionophores have been obtained due to the gradual perfection of the technology of plasticized poly(vinyl chloride) (PVC) matrix membranes. 

For the liquid-polymer mixed-matrix membranes, the physical state of the fillers incorporated into the continuous polymer matrix is liquid such as poly(ethylene glycol) (PEG). Because of the long-term stability concern of liquid polymer encapsulated in the continuous polymer matrix, a new type of mixed-matrix membranes, solid-hquid-polymer mixed-matrix membrane, has been developed recently. The solid such as activated carbon impregnated with liquid polymer such as PEG is functioned as stabilizer of the liquid polymer in the continuous polymer phase. Besides, activated carbon enhances the mixed-matrix membrane performance. 

For simplicity s sake all the membranes are hereafter addressed by writing in sequence the selected lithium salt, the liquid solvent (or solvent mixture) and the hosting polymer. For instance, the notation LiPFe-EC-DMC-PAN refers to a membrane formed by a solution of lithium hexafluorophosphate in a ethylene carbonate-dimethyl carbonate solvent mixture immobilized in a poly(acrylonitrile) matrix. 

Among all the polymers used in preparing ion-selective membranes, poly(vinylchloride) (PVC) is the most widely used matrix due to its simplicity of membrane preparation [32, 70], In order to ensure the mobility of the trapped ionophore, a large amount of plasticizer (approximately 66%) is used to modify the PVC membrane matrix (approximately 33%). Such a membrane is quite similar to the liquid phase, because diffusion coefficients for dissolved low molecular weight ionophores are high, on the order of 10 7-10 8cm2/s [59],... 

These types of separators consist of a solid matrix and a liquid phase, which is retained in the microporous structure by capillary forces. To be effective for batteries, the liquid in the microporous separator, which generally contains an organic phase, must be insoluble in the electrolyte, chemically stable, and still provide adequate ionic conductivity. Several types of polymers, such as polypropylene, polysulfone, poly(tetrafluoroethylene), and cellulose acetate, have been used for porous substrates for supported-liquid membranes. The PVdF coated polyolefin-based microporous membranes used in gel—polymer lithium-ion battery fall into this category. Gel polymer... 

Wieczorek, P., Tomaszewska, M. (1997). Transport ofamino acids through liquid membranes supported on novel poly(vinylidenefluoride) porous flat-sheet matrix. Solvent Extr. Ion. Exc., 15, 879-94. 

Lithium-Ion Cel Polymer Battery The Hthium-ion gel polymer batteries offer better performance than that of solid polymer electrolyte batteries. The gel electrolyte is a polymer matrix swollen with a liquid electrolyte, and the batteries that employ gel electrolyte are known as gel polymer batteries. The detailed information on this type of battery can be found in other chapters of this book and in a review [33]. Most of the gel electrolytes have been made employing PEO, poly(acrylonitrile) (PAN) [34], poly(methyl methacrylate) (PMMA) [35, 36], and PVdF [37, 38]. The poor mechanical properties of polymer and gel polymer electrolytes have led to an alternative approach where microporous membranes are impregnated with gel polymer electrolytes [39-42]. The process builds upon the work of Abraham et al. who saturated commercial polyolefin separators with a solution of lithium salt in a photopolymerizable monomer and a nonvolatile... 

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