Polymer/salt complexes host polymers

Solid polymer electrolytes (SPE) represent the newest and one of the most important (i.e. as far as potential applications are concerned) class of FIC solids. The area of polymer/salt complexes became extremely active following the work of Wright, who first reported that PEO is an excellent polymer host for a number of salts and that the resnlting polymer/salt complexes have significant electrical conductivities near room temperature. Armand extended the investigation of the electrical properties of the polymer/salt electrolytes and... 

Plasticized polymer-salt complexes are classified as gelled polymer electrolytes (GPE), fabricated by incorporating a large quantity of liquid plasticizer such as low molecular weight polyetlylene glycols or aptotic organic solvent to the polymer matrix-salt complex that is capable of forming a stmcturally stable gel like polymer host... 

Another approach extensively apphed in recerrt years to improve the ion conductivity ((, lithiirm ion transference number (C), mechanical properties, and the electrode-electrolyte interfacial stability of a polymer electrolyte is the addition of inorganic or ceramic fillers into the polymer-salt complexes (Capiglia et al., 1999 Kim et al., 2003 Chen-Yang et al., 2008 Croce et al., 2001 Rahman et al., 2009 Shen et al., 2009 Zhang et al., 2011 Munichandratah et al., 1995 Wiec-zorek, 1992). Micro and nano-sized inorganic filler such as silicone oxide (SiO ), alumina (AI2O3), ceria (CeO ), and so on are incorporated into PEO-salt complex in an effort to improve the mechanical, thermal stabihty, and ion conductivity of PEO-based polymer electrolytes. The effect of nano-fillers on the thermal properties of the PEO-based polymer complex varies with the type of nano-particles as well as the polymer-salt complex host matrix. 

An amorphous material sometimes referred to as amorphous poly(ethylene oxide), aPEO, consists of medium but randomly-variable length segments of poly(ethylene oxide) joined by methyleneoxide units. Fig. 5.13 (Wilson, Nicholas, Mobbs, Booth and Giles, 1990). These methyleneoxide units break up the regular helical pattern of poly(ethylene oxide) and in doing so suppress crystallisation. The aPEO host polymer and its salt complexes can crystallise below room temperature, but this is not detrimental to the properties of the polymer-salt complexes at or above room temperature. Similarly, dimethyl siloxy units have been introduced between medium length poly(ethylene oxide) units to produce an amorphous polymer. Fig. 5.14 (Nagoka, Naruse, Shinohara and Watanabe, 1984). 

Besides, the ceramic fillers provide surface conducting pathways as a result of its Lewis acid type interaction with the PEO chains, hence, promoting ion transport which leads to enhanced ion conductivity. The T of the polymer host matrix PEO-ammonium perchlorate (NH CIO ) investigated by Dey and Karan, (2008) arise in a narrow range between -41 °C and -46 °C while the of PEO-salt complex is lower than that of pure PEO upon addition of nano-CeO resulting in enhanced ion conductivity of the polymer nanocomposite (see Table 1). 

The insertion of PEO into mica-like sheet silicates in the reactions of a melt of the polymer with the host Na - or NH4 -exchanged lattice is one of tiie few examples of direct polymer intercalation. Poly(ethylene oxide) is also inserted into the lamellar networks of V205-nH20, MoOs," " - MnPSj, CdPSj, " etc. Thus an aqueous solution of PEO (M = 10 ) reacts with an aqueous gel of V2O5 nH20 to form a composite after removal of water. In this case, the interlayer distance increases from 1.155 to 1.32nm. Alkali metal ions react with PEO to form inclusion compounds. These can also be inserted into layers of ionic silicates, for example, into MMN. The distance between the layers of the PEO-Li salt complexes intercalated into MMN is 0.8 nm, the PEO chain adopts a slightly strained helicoid conformation in these locations. 

In these blends the counterion of the basic organic moiety acts as a surfactant and the covalently attached acidic group to this organic moiety forms a salt with an emeraldine macromolecule which can induce solute solvent interaction to give a tertiary system [9]. Cao et al [8] have reported that a complex of polyaniline and dopant can be co-dissolved in a common organic solvent at a desired ratio with a host polymer to form a solution of the polyblend. The polyblend can then be processed from solution to yield conducting transparent film/fibers with a electrical conductivities of about 1 S cm for a blend containing 2% polyaniline. This low volume of polyaniline required has been traced to a fibrillar well-connected network. 

ABSTRACT. A new polymer electrolyte Is described which was prepared by the reaction of poly(methylhydrosiloxane), PMHS, with poly(ethylene glycol), PEG, and poly(ethylene glycol methyl ether), MePEG. The glass transition temperature of the polymer host is very low (207 K) and the polymer forms complexes with the Li, Na, and K salts of trlfluoromethanesulfonate, all of which exhibit high ionic conductivi-... 

Examples of type I PEO-MX (M = multivalent cation, X = anion) include complexes of PEO-based calcium and barium salts, PEO-based zinc chloride (in composition O/Zn = 4 and 8), PE0-Cu(C104)2 (certain compositions) and PE0-Tm(S03CF3)3. When the polymeric system is predominantly amorphous, conductivity-temperature behaviour is sometimes better described by the VTF law, for instance for the gel polymer electrolyte studied by Pandey et a/., where the addition of liquid electrolyte provokes substantial conformational changes in the crystalline texture of the host polymer due to immobilisation of the liquid electrolyte in the gel system. The polymer crystallinity almost disappears and the VTF equation applies to the a-T relationship. 

Transition metal complexes are interesting as bio-inorganic model systems [155-157] and also because of their material properties (conductivity, magnetism, porosity) and as potential hosts for a variety of guests [156-161]. Whereas salt-like 2D-Cun-coordination polymers are well documented [158-162], far less is known about their neutral counterparts. 

Using a similar synthetic methodology, other water soluble polymers, such as poly(vinylpyrrolidinone) (PVP), polyfpropylene glycol) (PPG), and methyl cellulose (MCel) were intercalated into V20s.nH20 xerogels [41]. The ratio of intercalated polymer to the layered host could be synthetically manipulated. Similarly to PEO, PVP, PPG, and MCel could also function as solid electrolytes when complexed with lithium salts, and hence their relevance in lithium battery applications. The intercalation of PEO into V20snH20 was also reported by Ruiz-Hitzky et al. [42]. 

Glyeoluril-based hosts derivatized with crown ether moieties, such as 8, are known as molecular baskets beeause of their basket- or bowl-like shape (Fig. 2a). In addition to alkali metal ions and diatmnonium salts, these moleeules are excellent receptors for charged aromatic compounds such as viologens (MAT-disubstituted 4,4 -dipyridinium compounds) and polymeric derivatives thereof." Host 8 binds 9 with a of 5.7 x 10" M, which is much stronger than the binding of 9 in the hiXparaphenylene)-[34]-crown-10 macrocycle studied by Stoddart and coworkers. Upon complexation with 8, the redox properties of 9 were modified, i.e., bound 9 is 100 mV more difficult to reduce than uncomplexed 9. Once reduced to its 1+ form, however, 9 is expelled from the cavity. In the case of polymeric derivatives of 9, the electrochemical properties of the polymer are altered by the addition of Host 8. 

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