In an effort to develop free-standing lithium battery membrane, binary and ternary phase diagrams of poly(ethylene oxide) (PEO), bis(trifluoromethane)sulfonimide (LiTFSI), and succinonitrile (SCN) (i.e., solid plasticizer) mixtures have been established by means of differential scanning calorimetry and polarized optical microscopy. The occurrence of hydrogen bonds and/or coordination bonds in each binary pair (PEO/SCN, SCN/LiTFSI, and PEO/LiTFSI) was examined using Fourier transform infrared spectroscopy. The binary PEO/LiTFSI mixture exhibits a eutectic phase diagram with the liquid + crystal coexistence region having various crystal forms of the lithium salt, whereas the SCN/LiTFSI blend shows a wide noncrystalline region, which is highly desirable for organic solvent-free battery applications. The PEO/SCN blend shows a typical eutectic behavior, which is explicable in the framework of the Flory−Huggins theory in conjunction with the phase field theory of crystal solidification. Various coexistence regions of the PEO/SCN/LiTFSI mixtures have been mapped out using polarized optical microscopy and wide-angle X-ray diffraction. The ionic conductivity was determined at various coexistence regions such as isotropic noncrystalline liquid, crystal + liquid, liquid + plastic crystal regions using ac impedance spectroscopy. Of particular interest is that the conductivity in the isotropic liquid region is higher than those of the crystal (or plastic crystal) + liquid coexistence regions.

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Polyamide 6 has been reinforced by in situ polymerization of e-caprolactam by using either 2 wt % of multiwall carbon nanotubes of two different diameters and length or 2 wt % functionalized nonporous Stöber silica. The carbon nanotubes were synthesized by catalytic chemical vapor deposition of ethylene over two different supports: iron particles supported on MCM41 mesoporous silica and iron-cobalt particles on CaCO 3 , in order to produce multiwall carbon nanotubes with average diameter of 32 and 58 nm respectively. The Stöber silica particles with diameters of 85 nm and 150 nm were functionalized with 3-aminotrimethoxypropyl silane. The thermal stability of nanotubes/Polyamide 6 nanocomposites increases compared to the neat polyamide 6, and this increase is even larger when the functionalized silica nanoparticles are used as a filler. The crystallinity of polyamide is enhanced when carbon nanotubes are functionalized, but it decreases with or without functionalization of the silica particles. The nanotubes increase the temperature of crystallization in the nanocomposites due to the reduction in the mobility of polymer chains.